relay SSANGYONG NEW REXTON 2012 User Guide

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(13) PTC heater control
A. Overview
The supplementary electrical heater is installed in DI engine equipped vehicle as a basic equipment. The
PTC system is operated according to two temperature values measured at the coolant temperature
sensor and HFM sensor. This device is mounted in the heater air outlet and increase the temperature of
air to the passenger compartment. Because PTC system is heated by electrical power, high capacity
alternator is required. PTC does not operate during engine cranking, while the battery voltage is lower
than 11 V or during preheating process of glow plugs.
B. Components
HFM (intake air
temperature)
Coolant temperature
sensorPTC heaterD20DTR ECU
PTC 1 relay
PTC 2 relay
PTC 3 relay
PTC Fuse 3 (40A)PTC Fuse 2 (40A)PTC Fuse 1(40A)
Relay box in engine compartment

C. Operation process
The ceramic PTC has a feature that the resistance goes up very high at a certain temperature. There
are three circuits in PTC heater. Only one circuit is connected when PTC1 relay is ON, and two circuits
are connected when PTC2 relay is ON.

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D. PTC operation process
The PTC operating condition (ON) is controlled in two steps.
Basically, the engine ECU controls the relay to supply the power to PTC according to the coolant
temperature sensor and ambient temperature sensor.
1st step (initial operation of PTC)
-
-
-
-
-
Stop (OFF) conditions
A/C blower switch OFF
Defective ambient air temperature sensor (including open or short circuit)
Engine cranking
Low battery voltage (below 11V)
During pre-glow process (glow indicator ON) -
-
-
-
-

Engine Compartment Layout
Engine assembly
Engine oil dipstick
Vacuum pump
Oil filter and cooler
Fuel filter and priming pump
Brake booster
Brake oil tank
AQGS unit
Washer fluid filler cap
Engine compartment fuse box
PTC relay box
Battery
Vacuum modulator (for VGT turbo charger) 1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.FFH Assembly (Only for vehicle with FFH)
Power steering oil tank
Engine oil filler cap
Fan shroud
E-EGR Valve
High-capacity PCV oil separator
HFM sensor (6.0)
VGT turbo charger
Air cleaner housing
2Coolant surge tank
ABS/ESP HECU (Including TPMS function:
optional)
Exhaust gas FRT Temp. sensor (T3) 14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.

Engine Compartment Layout
Engine assembly
Engine oil dipstick
Vacuum pump
Oil filter and cooler
Fuel filter and priming pump
Brake booster
Brake oil tank
AQGS unit
Washer fluid filler cap
Engine compartment fuse box
PTC relay box
Battery
Vacuum modulator (for VGT turbo charger) 1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.FFH Assembly (Only for vehicle with FFH)
Power steering oil tank
Engine oil filler cap
Fan shroud
E-EGR Valve
High-capacity PCV oil separator
HFM sensor (6.0)
VGT turbo charger
Air cleaner housing
2Coolant surge tank
ABS/ESP HECU (Including TPMS function:
optional)
Exhaust gas FRT Temp. sensor (T3) 14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.