Ground DODGE RAM 1999 Service Repair Manual
Page 1546 of 1691
as the "peak" time, referring to the fact that current flow is allowed
to "peak" (to open the injector).
Once the injector pintle is open, the amp flow is
considerably reduced for the rest of the pulse duration to protect the
injector from overheating. This is okay because very little amperage
is needed to hold the injector open, typically in the area of one amp
or less. Some manufacturers refer to this as the "hold" time, meaning
that just enough current is allowed through the circuit to "hold" the
already-open injector open.
There are a couple methods of reducing the current. The most
common trims back the available voltage for the circuit, similar to
turning down a light at home with a dimmer.
The other method involves repeatedly cycling the circuit ON-
OFF. It does this so fast that the magnetic field never collapses and
the pintle stays open, but the current is still significantly reduced.
See the right side of Fig. 1 for an illustration.
The advantage to the current controlled driver circuit is the
short time period from when the driver transistor goes ON to when the
injector actually opens. This is a function of the speed with which
current flow reaches its peak due to the low circuit resistance. Also,
the injector closes faster when the driver turns OFF because of the
lower holding current.
NOTE: Never apply battery voltage directly across a low resistance
injector. This will cause injector damage from solenoid coil
overheating.
THE TWO WAYS INJECTOR CIRCUITS ARE WIRED
Like other circuits, injector circuits can be wired in one of
two fundamental directions. The first method is to steadily power the
injectors and have the computer driver switch the ground side of the
circuit. Conversely, the injectors can be steadily grounded while the
driver switches the power side of the circuit.
There is no performance benefit to either method. Voltage
controlled and current controlled drivers have been successfully
implemented both ways.
However, 95% percent of the systems are wired so the driver
controls the ground side of the circuit. Only a handful of systems use
the drivers on the power side of the circuit. Some examples of the
latter are the 1970's Cadillac EFI system, early Jeep 4.0 EFI (Renix
system), and Chrysler 1984-87 TBI.
INTERPRETING INJECTOR WAVEFORMS
INTERPRETING A VOLTAGE CONTROLLED PATTERN
NOTE: Voltage controlled drivers are also known as "Saturated
Switch" drivers. They typically require injector circuits
with a total leg resistance of 12 ohms or more.
NOTE: This example is based on a constant power/switched ground
circuit.
* See Fig. 2 for pattern that the following text describes.
Point "A" is where system voltage is supplied to the
injector. A good hot run voltage is usually 13.5 or more volts. This
point, commonly known as open circuit voltage, is critical because the
injector will not get sufficient current saturation if there is a
voltage shortfall. To obtain a good look at this precise point, you
Page 1547 of 1691
will need to shift your Lab Scope to five volts per division.
You will find that some systems have slight voltage
fluctuations here. This can occur if the injector feed wire is also
used to power up other cycling components, like the ignition coil(s).
Slight voltage fluctuations are normal and are no reason for concern.
Major voltage fluctuations are a different story, however. Major
voltage shifts on the injector feed line will create injector
performance problems. Look for excessive resistance problems in the
feed circuit if you see big shifts and repair as necessary.
Note that circuits with external injector resistors will not
be any different because the resistor does not affect open circuit
voltage.
Point "B" is where the driver completes the circuit to
ground. This point of the waveform should be a clean square point
straight down with no rounded edges. It is during this period that
current saturation of the injector windings is taking place and the
driver is heavily stressed. Weak drivers will distort this vertical
line.
Point "C" represents the voltage drop across the injector
windings. Point "C" should come very close to the ground reference
point, but not quite touch. This is because the driver has a small
amount of inherent resistance. Any significant offset from ground is
an indication of a resistance problem on the ground circuit that needs
repaired. You might miss this fault if you do not use the negative
battery post for your Lab Scope hook-up, so it is HIGHLY recommended
that you use the battery as your hook-up.
The points between "B" and "D" represent the time in
milliseconds that the injector is being energized or held open. This
line at Point "C" should remain flat. Any distortion or upward bend
indicates a ground problem, short problem, or a weak driver. Alert
readers will catch that this is exactly opposite of the current
controlled type drivers (explained in the next section), because they
bend upwards at this point.
How come the difference? Because of the total circuit
resistance. Voltage controlled driver circuits have a high resistance
of 12+ ohms that slows the building of the magnetic field in the
injector. Hence, no counter voltage is built up and the line remains
flat.
On the other hand, the current controlled driver circuit has
low resistance which allows for a rapid magnetic field build-up. This
causes a slight inductive rise (created by the effects of counter
voltage) and hence, the upward bend. You should not see that here with
voltage controlled circuits.
Point "D" represents the electrical condition of the injector
windings. The height of this voltage spike (inductive kick) is
proportional to the number of windings and the current flow through
them. The more current flow and greater number of windings, the more
potential for a greater inductive kick. The opposite is also true. The
less current flow or fewer windings means less inductive kick.
Typically you should see a minimum 35 volts at the top of Point "D".
If you do see approximately 35 volts, it is because a zener
diode is used with the driver to clamp the voltage. Make sure the
beginning top of the spike is squared off, indicating the zener dumped
the remainder of the spike. If it is not squared, that indicates the
spike is not strong enough to make the zener fully dump, meaning the
injector has a weak winding.
If a zener diode is not used in the computer, the spike from
a good injector will be 60 or more volts.
Point "E" brings us to a very interesting section. As you
can see, the voltage dissipates back to supply value after the peak of
the inductive kick. Notice the slight hump? This is actually the
mechanical injector pintle closing. Recall that moving an iron core
through a magnetic field will create a voltage surge. The pintle is
Page 1549 of 1691
drivers. They typically require injector circuits
with a total leg resistance with less than 12 ohm.
NOTE: This example is based on a constant power/switched ground
circuit.
* See Fig. 3 for pattern that the following text describes.
Point "A" is where system voltage is supplied to the
injector. A good hot run voltage is usually 13.5 or more volts. This
point, commonly known as open circuit voltage, is critical because the
injector will not get sufficient current saturation if there is a
voltage shortfall. To obtain a good look at this precise point, you
will need to shift your Lab Scope to five volts per division.
You will find that some systems have slight voltage
fluctuations here. This could occur if the injector feed wire is also
used to power up other cycling components, like the ignition coil(s).
Slight voltage fluctuations are normal and are no reason for concern.
Major voltage fluctuations are a different story, however. Major
voltage shifts on the injector feed line will create injector
performance problems. Look for excessive resistance problems in the
feed circuit if you see big shifts and repair as necessary.
Point "B" is where the driver completes the circuit to
ground. This point of the waveform should be a clean square point
straight down with no rounded edges. It is during this period that
current saturation of the injector windings is taking place and the
driver is heavily stressed. Weak drivers will distort this vertical
line.
Point "C" represents the voltage drop across the injector
windings. Point "C" should come very close to the ground reference
point, but not quite touch. This is because the driver has a small
amount of inherent resistance. Any significant offset from ground is
an indication of a resistance problem on the ground circuit that needs
repaired. You might miss this fault if you do not use the negative
battery post for your Lab Scope hook-up, so it is HIGHLY recommended
that you use the battery as your hook-up.
Right after Point "C", something interesting happens. Notice
the trace starts a normal upward bend. This slight inductive rise is
created by the effects of counter voltage and is normal. This is
because the low circuit resistance allowed a fast build-up of the
magnetic field, which in turn created the counter voltage.
Point "D" is the start of the current limiting, also known as
the "Hold" time. Before this point, the driver had allowed the current
to free-flow ("Peak") just to get the injector pintle open. By the
time point "D" occurs, the injector pintle has already opened and the
computer has just significantly throttled the current back. It does
this by only allowing a few volts through to maintain the minimum
current required to keep the pintle open.
The height of the voltage spike seen at the top of Point "D"
represents the electrical condition of the injector windings. The
height of this voltage spike (inductive kick) is proportional to the
number of windings and the current flow through them. The more current
flow and greater number of windings, the more potential for a greater
inductive kick. The opposite is also true. The less current flow or
fewer windings means less inductive kick. Typically you should see a
minimum 35 volts.
If you see approximately 35 volts, it is because a zener
diode is used with the driver to clamp the voltage. Make sure the
beginning top of the spike is squared off, indicating the zener dumped
the remainder of the spike. If it is not squared, that indicates the
spike is not strong enough to make the zener fully dump, meaning there
is a problem with a weak injector winding.
If a zener diode is not used in the computer, the spike from
Page 1562 of 1691
Fig. 21: Injector Bank - Known Good - Voltage Pattern
EXAMPLE #4 - CURRENT CONTROLLED DRIVER
From 1984 to 1987, Chrysler used this type injector drive on
their TBI-equipped engines. See Fig. 22 for a known-good pattern.
Instead of the ground side controlling the injector, Chrysler
permanently grounds out the injector and switches the power feed side.
Most systems do not work this way.
These injectors peak at 6 amps of current flow and hold at 1
amp.
Page 1590 of 1691
WIN DO W S - P O W ER
1999 D odge P ic ku p R 1500
1999 ACCESSORIES & EQUIPMENT
CHRY - Power Windows
Caravan, Dakota, Durango, Ram Pickup, Ram Van, Ram Wagon,
Town & Country, & Voyager
DESCRIPTION & OPERATION
A permanent magnet motor moves each of the power windows,
including power vent windows. A positive and negative battery
connection to either of the 2 motor terminals will cause the motor to
rotate in one direction. Reversing current through these same 2
connections will cause the motor to rotate in the opposite direction.
Each individual motor is grounded through the master switch by a wire
attached to the instrument panel reinforcement.
Caravan, Durango, Town & Country and Voyager are equipped
with an Auto Down feature. Drivers window can be lowered without
having to hold the switch in the down position. Auto Down feature can
be activated by pressing down switch past first detent. Caravan, Town
& Country and Voyager have optional power vent windows. Power rear
vent windows are operated by switches mounted in driver's door panel.
NOTE: Power window circuits on Caravan, Town & Country, and Voyager
use Positive Temperature Coefficient (PTC) devices. The PTC
is a specified amperage solid-state resettable fuse. PTCs are
located in junction box behind driver's side of instrument
panel, to left of steering column. To reset PTC, all current
must be removed from PTC for approximately 20 seconds.
ADJUSTMENTS
WINDOWS
Remove door trim panel. See DOOR TRIM PANEL under REMOVAL &
INSTALLATION. Loosen bolts holding window to regulator. Raise window
fully, seating window in frame. Tighten bolts. Install door trim
panel.
TROUBLE SHOOTING
CARAVAN, TOWN & COUNTRY, & VOYAGER
Inspect both No. 8 and 9 (9-amp) PTCs in junction block.
Junction block is located under left side of instrument panel.
* Inspect fuse No. 23 (40-amp) in Power Distribution Center
(PDC). PDC is located on left side of engine compartment.
* Inspect ground at instrument panel left side cowl.
DAKOTA & DURANGO
Inspect circuit breaker No. 20 (20-amp on Dakota, 25-amp on
Durango) in fuse block. Fuse block is located on left end of
instrument panel.
* Inspect fuse No. 9 (40-amp) in Power Distribution Center
(PDC). PDC is located in left front corner of engine
Page 1591 of 1691
compartment.
* Inspect power window system ground circuit. See WIRING
DIAGRAMS.
RAM PICKUP
Inspect fuse No. 2 (30-amp) located in Power Distribution
Center (PDC). PDC is located in left side of engine compartment.
* Inspect circuit breaker No. 1 (20-amp) in fuse block. Fuse
block is located under left side of instrument panel.
* Inspect power window system ground circuit. See WIRING
DIAGRAMS.
RAM VAN & RAM WAGON
Inspect circuit breaker No. 20 (20-amp) in junction block.
Junction block is located in left end of instrument panel.
* Inspect fuse No. 12 (40-amp) in Power Distribution Center
(PDC). PDC is located in left side of engine compartment.
* Inspect power window system ground circuit. See WIRING
DIAGRAMS.
COMPONENT TESTS
CIRCUIT BREAKER
Dakota, Durango, Ram Pickup, Ram Van & Ram Wagon
1) Locate circuit breaker for power window system. See
TROUBLE SHOOTING. Pull circuit breaker out slightly, but ensure
circuit breaker terminals still contact terminals in fuse block.
2) Connect voltmeter negative lead to ground. Using voltmeter
positive lead, check both terminals of circuit breaker for battery
voltage. If voltmeter indicates battery voltage at both terminals,
circuit breaker is okay.
3) If voltmeter indicates battery voltage at one terminal
only, replace faulty circuit breaker. If voltmeter indicates no
voltage at either terminal, check for an open or shorted circuit to
circuit breaker. Repair as necessary and recheck system operation.
VENT WINDOW MOTOR
Caravan, Town & Country, & Voyager
1) Remove "D" pillar trim panel. See "D" PILLAR TRIM PANEL
under REMOVAL & INSTALLATION. Disconnect vent window motor connector.
Using jumper wires, apply battery voltage to vent window motor
terminals. Motor should rotate in one direction, moving window open or
closed. If window is in full closed or open position, no movement will
be observed and motor will make a grunting noise.
2) Reverse battery leads. Window should move in opposite
direction. If window does not move or window does not make a grunting
noise, replace vent window motor. If window moved completely open and
closed, motor should be reversed one more time to complete a full
window movement inspection.
3) If motor grunts and window does not move, remove motor
assembly. Check window motor crank for binding. Repair as necessary.
Recheck window operation. If window moves, check power window switch
continuity. See POWER WINDOW SWITCH. Replace switch as necessary. If
window switch is okay, check for open circuit between window motor and
window switch. See WIRING DIAGRAMS. Repair as necessary.
Page 1595 of 1691
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Switch Position Continuity Between Terminals
Off ................................ 1 & 13; 2 & 13; 3 & 13; 4 & 13;
5 & 13; 6 & 13, 7 & 13; 8 & 13 Up
Driver's Side ............................................. 8 & 11
Passenger's Side ........................................... 4 & 9
Down
Driver's Side (1) ......................................... 6 & 11
Passenger's Side ........................................... 2 & 9
Auto-Down
Driver Side's ( 1) ......................................... 6 & 11
Vent Open
Left ...................................................... 7 & 11
Right ...................................................... 1 & 9
Vent Close
Left ....................................................... 3 & 9
Right ..................................................... 5 & 11
( 1) - Connect battery voltage to terminal No. 9 and ground to terminal
No. 13 before testing.
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DRIVER'S WINDOW SWITCH CONTINUITY (DAKOTA & RAM PICKUP) \
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Switch Position Continuity Between Terminals
Off ..................................... 1 & 3; 2 & 3; 3 & 4; 3 & 6
Up
Left ................................................ 3 & 4; 5 & 6
Right ............................................... 1 & 5; 2 & 3
Down
Left ................................................ 3 & 6; 4 & 5
Right ............................................... 1 & 3; 2 & 5
Light ........................................................ 3 & 5
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DRIVER'S WINDOW SWITCH CONTINUITY (DURANGO) \
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Switch Position Continuity Between Terminals
Off ................................... 2 & 5; 3 & 5; 5 & 6; 5 & 11;
5 & 12; 5 & 13; 5 & 14
Up
Left Front ( 1) ............................................. 4 & 6
Right Front ......................................... 2 & 5; 3 & 4
Left Rear ......................................... 4 & 14; 5 & 13
Right Rear ........................................ 4 & 12; 5 & 11
Down
Left Front ( 1) ............................................. 5 & 6
Right Front ......................................... 2 & 4; 3 & 5
Left Rear ......................................... 4 & 13; 5 & 14
Right Rear ........................................ 4 & 11; 5 & 12
Auto-Down
Left Front ................................................... ( 1)
Power Window Lock-Out ........................................ 4 & 7
( 1) - Vehicles equipped with Auto Down feature have electronic
components in switch to actuate Auto Down. To test,
check switch continuity, reconnect switch, turn ignition on and
test feature. If Auto Down does not work, replace switch.
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Page 1596 of 1691
DRIVER'S WINDOW SWITCH CONTINUITY (RAM VAN & RAM WAGON) \
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Switch Position Continuity Between Terminals
Off ..................................... 1 & 2; 2 & 3; 3 & 4; 4 & 6
Up
Left .................................. 1 & 5; 2 & 3; 3 & 4; 4 & 6
Right ................................. 1 & 2; 2 & 4; 3 & 5; 4 & 6
Down
Left .................................. 1 & 2; 2 & 3; 3 & 4; 5 & 6
Right ................................. 1 & 2; 2 & 3; 3 & 6; 4 & 5
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PASSENGER'S WINDOW SWITCH CONTINUITY (CARAVAN, TOWN & COUNTRY, &
VOYAGER)
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Switch Position Continuity Between Terminals
Off ................................................... 2 & 5; 3 & 8
Up ........................................................... 4 & 8
Down ......................................................... 4 & 5
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PASSENGER'S WINDOW SWITCH CONTINUITY (DAKOTA & RAM PICKUP) \
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Switch Position Continuity Between Terminals
Off ................................................... 1 & 4; 2 & 3
Up ................................................... 2 & 3; 4 & 11
Down ................................................. 1 & 4; 3 & 11
Light ....................................................... 8 & 11
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PASSENGER'S WINDOW SWITCH CONTINUITY (DURANGO) \
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Switch Position Continuity Between Terminals
Off ................................................... 2 & 5; 3 & 6
Up .................................................... 2 & 5; 3 & 4
Down .................................................. 3 & 6; 4 & 5
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PASSENGER'S WINDOW SWITCH CONTINUITY (RAM VAN & RAM WAGON) \
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Switch Position Continuity Between Terminals
Off ................................................... 1 & 4; 2 & 3
Up .................................................... 1 & 4; 3 & 5
Down .................................................. 2 & 3; 1 & 5
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SYSTEM TESTS
ALL WINDOWS INOPERATIVE
Caravan, Town & Country, & Voyager
1) Check Positive Temperature Coefficient (PTC) for power
window system. See TROUBLE SHOOTING. Replace PTC as necessary. If PTC
is okay, go to next step.
2) Remove driver's power window switch. See POWER WINDOW
SWITCH under REMOVAL & INSTALLATION. Turn ignition on. Using test
light, connect ground lead to harness connector terminal No. 13 (Black
Page 1597 of 1691
Wire). Check for voltage by touching test light probe to harness
connector terminals No. 9 (Tan/Dark Green Wire) and No. 11 (Tan Wire)\
.
3) If test light illuminates, ground circuit and circuit
between battery and switch are okay. If test light does not
illuminate, check power and ground circuits. See WIRING DIAGRAMS.
Dakota & Ram Pickup
1) Check circuit breaker for power window system. See TROUBLE
SHOOTING. Replace circuit breaker as necessary. If circuit breaker is
okay, go to next step.
2) Remove driver's front power window switch. See POWER
WINDOW SWITCH under REMOVAL & INSTALLATION. Check for continuity
between ground and terminal No. 3 at driver power window switch wiring
harness connector. See WIRING DIAGRAMS. If continuity exists, go to
next step. If continuity does not exist, repair open in Black/Light
Green wire (Ram Pickup) or Black wire (Dakota) between driver power
window switch connector and ground.
3) Turn ignition on. Measure voltage between ground and
terminal No. 5 (Tan wire) at driver's power window switch wiring
harness connector. If battery voltage is present, check driver power
window switch. See POWER WINDOW SWITCH under COMPONENT TESTS. If
battery voltage is not present, repair open Tan wire between driver
power window switch connector and ignition switch. See WIRING
DIAGRAMS.
Durango
1) Check circuit breaker for power window system. See TROUBLE
SHOOTING. Replace circuit breaker as necessary. If circuit breaker is
okay, go to next step.
2) Disconnect negative battery cable. Remove driver's front
power window switch. See POWER WINDOW SWITCH under REMOVAL &
INSTALLATION.
3) Check for continuity between ground and terminal No. 5
(Black wire) at driver's power window switch wiring harness connector.\
See WIRING DIAGRAMS. If continuity exists, go to next step. If
continuity does not exist, repair open in Black wire between driver's
power window switch connector and ground.
4) Reconnect negative battery cable. Turn ignition on.
Measure voltage between ground and terminal No. 4 (Tan wire) at
driver's power window switch wiring harness connector. If battery
voltage is present, check driver's power window switch. See POWER
WINDOW SWITCH under COMPONENT TESTS. If battery voltage is not
present, repair open Tan wire between driver power window switch
connector and ignition switch. See WIRING DIAGRAMS.
Ram Van & Ram Wagon
1) Check circuit breaker for power window system. See TROUBLE
SHOOTING. Replace circuit breaker as necessary. If circuit breaker is
okay, go to next step.
2) Remove driver's front power window switch. See POWER
WINDOW SWITCH under REMOVAL & INSTALLATION. Check for continuity
between ground and driver power window switch wiring harness connector
terminal No. 2 (Black wire). If continuity exists, go to next step. If\
continuity does not exist, repair open in Black wire between driver
power window switch connector and ground.
3) Check for battery voltage at driver's power window switch
harness connector terminal No. 5. If battery voltage exists, check
window switch. See POWER WINDOW SWITCH under COMPONENT TESTS. If
battery voltage does not exist, repair open Tan wire.
ONE WINDOW INOPERATIVE
NOTE: Window glass must be free to slide up and down for power
Page 1598 of 1691
window motor to function properly. If glass is not free to
move up and down, motor will overload and trip the circuit
breaker.
Dakota & Ram Pickup
1) Place window glass halfway between up and down positions.
Verify glass can be moved slightly from side to side, front to rear,
and up and down. If glass does not move freely, check window glass,
tracks and regulator for sticking, binding or improper adjustment.
Repair as necessary and recheck system operation. If glass moves
freely, go to next step.
2) Disconnect negative battery cable. Remove power window
switch from door with inoperative window. Disconnect power window
switch connector. Connect negative battery cable. Turn ignition on.
Check for battery voltage at power window switch harness connector
terminal No. 5 (driver's window) or terminal No. 11 (passenger's
window). If battery voltage does not exist, repair open Tan wire
between junction block and power window switch. If battery voltage
exists, go to next step (inoperative passenger's window) or go step 4)\
(inoperative driver's window).
3) Disconnect negative battery cable. Check for continuity
between ground and passenger window switch harness connector terminals
No. 1 (Brown/White wire) and 2 (Violet/White wire). If continuity
exists, go to next step. If continuity does not exist, repair open
circuit in wiring harness between window switches.
4) Check power window switch. See POWER WINDOW SWITCH under
COMPONENT TESTS. Replace faulty power window switch as necessary. If
switch is okay, go to next step.
5) Check for continuity between window switch wiring
connector terminals and corresponding window motor wire connector
terminals of inoperative power window. If continuity exists in all
circuits, power window switch and switch circuits are okay. Check
power window motor. See POWER WINDOW MOTOR under COMPONENT TESTS. If
continuity does not exist in one or more circuits, repair open
circuit(s) as necessary. Recheck system operation.
Durango
1) Place window glass halfway between up and down positions.
Verify glass can be moved slightly from side to side, front to rear,
and up and down. If glass does not move freely, check window glass,
tracks and regulator for sticking, binding or improper adjustment.
Repair as necessary and recheck system operation. If glass moves
freely, and is not driver's window, go to next step. If driver's
window is inoperative, check power window motor. See POWER WINDOW
MOTOR under COMPONENT TESTS. If Auto Down feature is the only problem,
replace driver's switch. If switch LED is the only problem, replace
unlit switch.
2) Disconnect negative battery cable. Remove power window
switch from door with inoperative window. See POWER WINDOW SWITCH
under REMOVAL & INSTALLATION. Connect negative battery cable. Turn
ignition on. Check for battery voltage at power window switch harness
connector Yellow wire. If battery voltage does not exist, repair open
circuit to master window switch. If battery voltage exists, go to next
step.
3) Test power window switch continuity. See POWER WINDOW
SWITCH under COMPONENT TESTS. Replace faulty switch as necessary. If
switch is okay, go to next step.
4) Check for continuity in each circuit between master window
switch and switch for inoperative window. See WIRING DIAGRAMS. If
continuity does not exist in any circuit, repair open circuit as
necessary. If continuity exists in all circuits, test power window
motor. See POWER WINDOW MOTOR under COMPONENT TESTS.