overheating DODGE RAM 1999 Service Repair Manual

[x] Cancel search | Manufacturer: DODGE, Model Year: 1999, Model line: RAM, Model: DODGE RAM 1999
Pages: 1691, PDF Size: 40.34 MB

Page 43 of 1691

DODGE RAM 1999 Service Repair Manual HIGH
Some possible causes of low side system pressure being high-
to-normal and high side system pressure being too high include:
* Condenser air flow restricted.
* In

HIGH
Some possible causes of low side system pressure being high-
to-normal and high side system pressure being too high include:
* Condenser air flow restricted.
* Inoperative cooling fan.
* Faulty expansion valve.
* Refrigerant system overcharged.
* Air in refrigerant system.
* Engine overheating.
LOW SIDE PRESSURE IS HIGH & HIGH SIDE PRESSURE IS LOW
Some possible causes of low side system pressure being too
high and high side system pressure being too low include:
* Compressor belt is slipping.
* Fixed orifice tube not installed.
* Faulty compressor.
LOW SIDE PRESSURE IS LOW & HIGH SIDE PRESSURE IS HIGH
Some possible causes of low side system pressure being too
low and high side system pressure being too high include:
* Restricted refrigerant flow through refrigerant lines.
* Restricted refrigerant flow through expansion valve.
* Restricted refrigerant flow through fixed orifice tube.
* Restricted refrigerant flow through receiver-drier.
* Restricted refrigerant flow through condenser.
BLOWER MOTOR DIAGNOSIS
BLOWER MOTOR INOPERATIVE
Some possible causes of an inoperative blower motor include:
* Faulty fuse.
* Faulty blower motor feed circuit wire harness or
connectors.
* Faulty blower motor ground circuit wire harness or
connector.
* Faulty blower motor resistor.
* Faulty blower motor relay.
* Faulty blower motor switch.
* Faulty A/C-heater mode control switch.
* Faulty blower motor.
BLOWER NOT OPERATING IN ALL SPEEDS
Possible causes of the blower not operating in all speeds
include:
* Faulty fuse.
* Faulty blower motor feed circuit wire harness or
connectors.
* Faulty blower motor relay.
* Faulty blower motor resistor.
* Faulty blower motor switch.

Page 63 of 1691

DODGE RAM 1999 Service Repair Manual Connector missing ....... C ............ Require replacement.
Inoperative ............. A ........ (2) Require replacement.
Insulation overheated ... A ............ Require replacement.
Te

Connector missing ....... C ............ Require replacement.
Inoperative ............. A ........ (2) Require replacement.
Insulation overheated ... A ............ Require replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A ........... ( 1) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
( 1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Inoperative includes intermittent operation or out of
OEM specification.
\
\
\
\
\
\
\

BLOWER SWITCHES
See SWITCHES.
CABIN AIR FILTERS
CABIN AIR FILTER INSPECTION\
\
\
\
\
\
\

Condition Code Procedure
Air flow obstruction .... A ............. Require cleaning or
replacement.
Maintenance intervals ... 3 ............ Suggest replacement.
Missing ................. C ............ Require replacement.
\
\
\
\
\
\
\

CIRCUIT BREAKERS
See FUSES, FUSIBLE LINKS AND CIRCUIT BREAKERS .
COMPRESSOR CLUTCH ASSEMBLIES
COMPRESSOR CLUTCH ASSEMBLY INSPECTION\
\
\
\
\
\
\

Condition Code Procedure
Air gap incorrect ....... B .. Require repair or replacement.
Bearing seized .......... A .. Require replacement of bearing
or assembly.
Bearing worn, affecting
performance ............ A .. Require replacement of bearing
or assembly.
Coil shows signs of
overheating ............ 1 .... Suggest replacement of coil.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted,

Page 119 of 1691

Page 745 of 1691

DODGE RAM 1999 Service Repair Manual (1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Determine source of contamination, such as engine
coolant, fuel, metal particles, or water. Require
r

(1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Determine source of contamination, such as engine
coolant, fuel, metal particles, or water. Require
repair or replacement.
( 3) - Inoperative includes intermittent operation or out of
OEM specification. Some components may be serviceable;
check for accepted cleaning procedure.
\
\
\
\
\
\
\

ENGINE COOLING SYSTEMS
NOTE: Overheating, poor engine performance, and insufficient
cabin heat can be affected by, but are not limited to,
all of the components in the engine cooling system.
ENGINE COVERS (OIL PAN, VALVE COVER, TIMING COVER)
ENGINE COVER (OIL PAN, VALVE COVER, TIMING COVER) INSPECTION\
\
\
\
\
\
\

Condition Code Procedure
Attaching hardware
incorrect .............. B ............ Require replacement.
Attaching hardware
loose .................. A .. Require repair or replacement.
Attaching hardware
missing ................ C ............ Require replacement.
Baffle loose ............ 2 .. Suggest repair or replacement.
Baffle missing .......... C ............ Require replacement.
Bent, affecting
performance ............ A .. Require repair or replacement.
Bent, not affecting
performance ............ .. ....... No service suggested or
required.
Cracked (not leaking) ... 2 .. Suggest repair or replacement.
Leaking externally ...... A .. Require repair or replacement.
Leaking internally,
causing fluid
contamination .......... A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Restricted passage ...... A .. Require repair or replacement.
Threads damaged ......... A .. Require repair or replacement.
\
\
\
\
\
\
\

ENGINE OIL
ENGINE OIL INSPECTION\
\
\
\
\
\
\

Condition Code Procedure
Contaminated ............ A .. ( 1) Require replacement of oil
and filter.
Level high .............. B ... Determine source of incorrect
level and require repair.
Level low ............... B ... Determine source of incorrect
level and require repair.
Maintenance intervals ... 3 ... Suggest replacement to comply
with vehicle's OEM recommended
service intervals.
( 1) - Determine source of contamination, such as engine coolant,
fuel, metal particles, or water when changing oil. Require

Page 767 of 1691

DODGE RAM 1999 Service Repair Manual replacement.
Connector missing ....... C ............ Require replacement.
Corroded, affecting
performance ............ A ............ Req

replacement.
Connector missing ....... C ............ Require replacement.
Corroded, affecting
performance ............ A ............ Require replacement.
Corroded, not affecting
performance ............ 2 ............ Suggest replacement.
Distorted ............... .. .... (2) No service suggested or
required.
Inoperative ............. A ........ ( 3) Require replacement.
Oil leaking ............. A ............ Require replacement.
Out of specification .... B ............ Require replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A ........... ( 1) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead corroded ...... A .. Require repair or replacement.
Wire lead open .......... A .. Require repair or replacement.
Wire lead shorted ....... A .. Require repair or replacement.
( 1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Distortion may be the result of overheating; coil should
be tested.
( 3) - Inoperative includes intermittent operation.
\
\
\
\
\
\
\

IGNITION CONTROL MODULES (ICM)
IGNITION CONTROL MODULE (ICM) INSPECTION\
\
\
\
\
\
\

Condition Code Procedure
Application incorrect ... B ............ Require replacement.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware
threads damaged ........ A ... Require repair or replacement
of hardware.
Attaching hardware
threads stripped
(threads missing) ...... A ... Require repair or replacement
of hardware.
Code set
(if applicable) ........ A .......... ( 1) Further inspection
required.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted ........ A ........... ( 2) Require repair or
replacement.

Page 813 of 1691

DODGE RAM 1999 Service Repair Manual loose .................. A ... Require repair or replacement
of injection tube or
replacement of catalytic

loose .................. A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
restricted ............. A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
threads damaged ........ A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
threads stripped
(threads missing) ...... A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Body cracked ............ B .. Require repair or replacement.
Converter empty ......... A .. Require repair or replacement.
Converter fill plug
missing ................ C .. Require repair or replacement.
Converter missing ....... C ............ Require replacement.
Exhaust gases leaking ... A .. Require repair or replacement.
Flanges leaking ......... A ... Require repair or replacement
of flanges.
Inlet pipes cracked ..... B .. Require repair or replacement.
Internal rattle (except
pellet-type) ........... 2 .......... (1) Further inspection
required.
Mounting brackets that
are part of converter
broken ................. A .. Require repair or replacement.
Obvious overheating ..... .. ......... ( 2) Require testing of
converter.
Outlet pipes cracked .... B .. Require repair or replacement.
Pieces of catalyst
material found
downstream ............. 1 ............ Suggest replacement.
Plugged ................. A ........ ( 3) Require replacement.
Testing has determined
that existing converter
has been lead-poisoned,
contaminated, or failed
testing ................ A .. Require repair or replacement.
( 1) - If the converter is breaking up, suggest converter
replacement. If an object has fallen into the converter,
remove the object.
( 2) - Overheating is caused by something other than the
converter. Further diagnosis is required to determine
the cause of the overheating.
( 3) - Determine cause and correct to ensure that new converter
will not become plugged.
\
\
\
\
\
\
\

EXHAUST AND TAIL PIPES
NOTE: For pipes with resonators, also see MUFFLERS AND RESONATORS.
EXHAUST AND TAIL PIPE INSPECTION

Page 1545 of 1691

DODGE RAM 1999 Service Repair Manual times by increasing injector pulse width accordingly.
NOTE: Never apply battery voltage directly across a low resistance
injector. This will cause injector damage from solenoid coil

Page 1546 of 1691

DODGE RAM 1999 Service Repair Manual 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

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