1999 DODGE RAM heater

Transmission Overdrive Switch (A/T Models)
See TRANSMISSION under MISCELLANEOUS CONTROLS.
RELAYS & SOLENOIDS
RELAYS
A/C Clutch Relay
A/C clutch relay may also be referred to as A/C compressor
clutch relay. A/C clutch relay is located in power distribution center
at driver's side front corner of engine compartment, near battery. If
problem exists in A/C clutch relay or wiring circuit, a Diagnostic
Trouble Code (DTC) will be stored in Powertrain Control Module (PCM)\
.
See DTC P0645 in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
Auto Shutdown (ASD) Relay
ASD relay is located in power distribution center at driver's
side front corner of engine compartment, near battery. If problem
exists in ASD relay or wiring circuit, a Diagnostic Trouble Code (DTC)\
will be stored in Powertrain Control Module (PCM). See SELF-
DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
Fuel Heater Relay
1) Fuel heater relay is located in Power Distribution Center
(PDC) next to left battery. Refer to PDC lid for relay location.
Remove relay and note terminal identification on relay. See Fig. 3.
2) Using ohmmeter, check resistance between terminals No. 85
and 86 on relay. Resistance should be 70-80 ohms. If resistance is
within specification, go to next step. If resistance is not within
specification, replace relay.
3) Using ohmmeter, ensure continuity exists between terminals
No. 30 and 87A on relay. If continuity exists, go to next step. If no
continuity exists, replace relay.
4) Using ohmmeter, ensure no continuity exists between
terminals No. 30 and 87 on relay. If no continuity exists, go to next
step. If continuity exists, replace relay.
5) Using jumper wires, connect terminal No. 85 to negative
side of 12-volt power source and terminal No. 86 to positive side of
12-volt power source. Using ohmmeter, ensure no continuity now exists
between terminals No. 30 and 87A on relay. If no continuity exists, go
to next step. If continuity exists, replace relay.
CAUTION: DO NOT allow ohmmeter leads to contact terminals No. 85 and
86 on relay when checking resistance.
6) Using ohmmeter, ensure continuity now exists between
terminals No. 30 and 87 on relay. If continuity exists, disconnect
jumper wires from relay. If no continuity exists, replace relay.
NOTE: For additional information on checking wiring circuit for
fuel heater relay, see TEST NTC-1: NO TROUBLE CODE TEST MENU
and TEST NS-SEL: NO START TEST SELECTION in SELF-DIAGNOSTICS
- JEEP, TRUCKS & RWD VANS article.

Fig. 3: Fuel Heater Relay Terminals
Courtesy of Chrysler Corp.
Intake Manifold Air Heater Relays
1) Intake manifold air heater relays may also be referred to
as intake air heater relays. Intake manifold air heater relays are
mounted on inner wheelwell, below driver's side battery. See Fig. 4.
2) Disconnect negative battery cables. Note location of
wiring on intake manifold air heater relays for reassembly reference.
Disconnect all electrical connectors and cables from intake manifold
air heater relays.
3) Connect ohmmeter between large terminals on intake
manifold air heater relay to check for continuity. Using jumper wires,
momentarily apply battery voltage to relay trigger wire terminals
(small wire terminals) at base of intake manifold air heater relay.
See Fig. 4 . Polarity is not important.
4) Intake manifold air heater relay should click and ohmmeter
should indicate continuity between large terminals when battery
voltage is applied to relay trigger wire terminals. If intake manifold
air heater relay operation is not as specified, replace intake
manifold air heater relay with bracket. Test remaining intake manifold
air heater relay. Remove ohmmeter. Reconnect all electrical connectors
and negative battery cables.
NOTE: For additional information on checking wiring circuit for
intake manifold air heater relay, see DTC P0380: INTAKE AIR
HEATER RELAY NO. 1 CONTROL CIRCUIT and DTC P0382: INTAKE AIR
HEATER RELAY NO. 2 CONTROL CIRCUIT tests in SELF-DIAGNOSTICS
- JEEP, TRUCKS & RWD VANS article.

Fig. 4: Locating Intake Manifold Air Heater Relays
Courtesy of Chrysler Corp.
Transmission Relay (A/T Models)
Transmission relay may be referred to as transmission control
relay or transmission 12-volt supply relay. Transmission relay is
located in power distribution center at driver's side front corner of
engine compartment, near battery. If problem exists in transmission
relay or wiring circuit, a Diagnostic Trouble Code (DTC) will be
stored in Powertrain Control Module (PCM). See DTC P1765: TRANSMISSION\
12-VOLT SUPPLY RELAY CONTROL CIRCUIT test in SELF-DIAGNOSTICS - JEEP,
TRUCKS & RWD VANS article.
SOLENOIDS
Transmission Overdrive Solenoid (A/T Models)
See TRANSMISSION under MISCELLANEOUS CONTROLS.

FUEL DELIVERY
Fuel Filter/Water Separator
1) A restricted fuel filter/water separator may cause engine
starting problems, prevent engine from accelerating, low power or
White exhaust smoke.
2) When ignition is first turned on, WATER-IN-FUEL (WIF)
warning light should come on for 2 seconds to perform bulb and wiring
circuit test and then go off. WATER-IN-FUEL (WIF) warning light is
located on instrument panel, just below tachometer.
3) If WATER-IN-FUEL (WIF) warning light stays on, water
should be drained from fuel filter/water separator. To drain water
from fuel filter/water separator, ensure engine is not running. Place
drain pan below drain tube at fuel filter/water separator.
4) Rotate handle on drain valve forward, toward front of
vehicle to DRAIN position. Drain valve is located near top of fuel
filter/water separator.
5) If no water exists and a clean flow of diesel fuel exists,
rotate handle on drain valve back to CLOSE position. Go to next step.
If water exists, allow water to drain until clean flow of diesel fuel
exists. Rotate handle on drain valve back to CLOSE position. Go to
next step.
6) Verify fuel filter/water separator has been serviced
according to proper service schedule. See SERVICE & ADJUSTMENT
SPECIFICATIONS - TRUCKS article. Ensure pre-filter was cleaned when
fuel filter/water separator was serviced. Pre-filter is located at
bottom of fuel heater on driver's side of engine. No other testing
information is available from manufacturer.
Fuel Heater
1) Malfunctioning fuel heater may cause excessive wax build-
up in fuel filter/water separator during cold ambient temperatures.
Wax build-up may cause hard starting, prevent engine from
accelerating, low power, or Blue or White smoke.
2) Disconnect electrical connector at fuel heater. Fuel
heater is located in top of fuel filter housing. Using ohmmeter, check
resistance between electrical terminals on fuel heater.
3) Resistance should be about one ohm when fuel is cold, and
about 1000 ohms when fuel is warm. Replace fuel heater if resistance
is not within specification.
NOTE: Fuel heater receives battery voltage from fuel heater relay.
Fuel heater relay is located in Power Distribution Center
(PDC), next to left battery. Refer to PDC lid for relay
location. For testing of fuel heater relay, see RELAYS under
RELAYS & SOLENOIDS. Consult wiring diagram for wiring circuit
testing. See appropriate wiring diagram in WIRING DIAGRAMS
article.
Fuel Transfer Pump Preliminary Inspection
1) Check for restricted or leaking fuel supply line to fuel
transfer pump or fuel return line located on driver's side of engine.
Repair fuel supply line or fuel return line if restricted or leaking.
2) Check for fuel leaking from weep hole on housing of fuel
transfer pump. Replace fuel transfer pump if fuel is leaking from weep
hole. Check fuel transfer pump for output pressure, pressure drop,
supply restriction, and air leaks.
NOTE: Separate pressure tests are necessary because transfer pump
operates at 2 pressure cycles, depending on whether engine is
running or cranking.

NOTE: A leaking fuel injector or high-pressure fuel line may cause
a rough idle, Black smoke, poor engine performance, poor fuel
economy and fuel knock. Following procedure is for
determining if fuel injector is defective.
WARNING: DO NOT allow diesel fuel to contact hot engine when checking
fuel injector, as high exhaust temperatures could cause a
fire. Use care when working around high-pressure fuel lines,
as fuel is under extreme pressure and could penetrate skin,
causing personal injury. Wear safety goggles and protective
clothing when checking fuel injectors.
Fuel Injector
1) Since a leaking high-pressure fuel line may cause the same
symptoms, check for leaking high-pressure fuel line before checking
fuel injector. To check for a leaking high-pressure fuel line, start
engine and allow engine to idle.
2) Inspect high-pressure fuel lines and connections for signs
of fuel leakage by placing cardboard over high-pressure fuel line and
connection. Note if leak is being detected by fuel being sprayed onto
cardboard. If leak exists, repair leak by tightening high-pressure
fuel line nut to 18 ft. lbs. (24 N.m) or replacing high-pressure fuel
line as necessary. If high-pressure fuel line is replaced, bleed air
from fuel system. See FUEL LINE BLEEDING under FUEL SYSTEM in REMOVAL,
OVERHAUL & INSTALLATION article.
3) To check for defective fuel injector, start and idle
engine. Loosen high-pressure fuel line nut at fuel injector and listen
for a decrease in engine speed. Tighten high-pressure fuel line nut to
18 ft. lbs. (24 N.m).
4) If fuel injector is operating properly, engine idle speed
should decrease when high-pressure fuel line nut is loosened. Repeat
procedure on each fuel injector.
5) If engine idle speed does not decrease, fuel injector is
defective and should be removed and tested with a diesel fuel injector
tester. Replace fuel injector if fuel injector opening (pop) pressure
is not about 4500 psi (316 kg/cm

).
EMISSION SYSTEMS & SUB-SYSTEMS
INTAKE MANIFOLD AIR HEATER SYSTEM
Intake Manifold Air Heater Preheat/Postheat Cycle
For testing information on intake manifold air heater system,
see DTC P0380: INTAKE AIR HEATER RELAY NO. 1 CONTROL CIRCUIT and DTC
P0382: INTAKE AIR HEATER RELAY NO. 2 CONTROL CIRCUIT tests in SELF-
DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
MISCELLANEOUS CONTROLS
NOTE: Although some controlled devices listed here are not
technically engine performance components, they can affect
driveability if they malfunction.
TRANSMISSION
Park/Neutral Switch (A/T Models)
Park/neutral switch is mounted on transmission case, near
shift lever and contains a 3-pin connector. If problem exists in
park/neutral switch or wiring circuit, a Diagnostic Trouble Code (DTC)\
will be stored in Powertrain Control Module (PCM). See DTC P1899: P/N
SWITCH STUCK IN PARK OR IN GEAR test in SELF-DIAGNOSTICS - JEEP,

SYSTE M W IR IN G D IA G RAM S

1999 D odge P ic ku p R 1500
1999 System Wiring Diagrams
Dodge - Pickup R1500
AIR CONDITIONING
Heater Circuit

* Air in fuel system:
* Coolant leak into combustion chamber:
* Block heater malfunction in cold weather:
* Clogged or defective fuel filter:
* Poor fuel quality:
* Fuel injector malfunctioning or loose:
* Restricted or blocked fuel injection or supply lines:
* Intake/exhaust valves not adjusted properly (tight):
* Intake heaters malfunctioning:
* Internal engine damage.
BLUE EXHAUST SMOKE
* Air filter dirty or plugged:
* Air intake system restricted:
* Air leak in intake between turbocharger and intake
manifold:
* Restricted exhaust:
* Restricted turbocharger drain tube:
* Crankcase ventilation plugged:
* Valve stems, guides or seals worn or defective:
* Piston rings improperly gapped, worn or broken:
* Internal engine wear:
* Turbocharger failure.
INTERMITTENTS
INTERMITTENT PROBLEM DIAGNOSIS
Intermittent fault testing requires duplicating circuit or
component failure to identify problem. These procedures may lead to
PCM setting a Diagnostic Trouble Code (FTC) which may help in
diagnosis.
If problem vehicle does not produce DTCs, monitor voltage or
resistance values using a Digital Volt-Ohmmeter (DVOM) while
attempting to reproduce conditions causing intermittent fault. A
status change on DVOM indicates a fault has been located.
Use a DVOM to pinpoint faults. When monitoring voltage,
ensure ignition switch is in ON position or engine is running. Ensure
ignition switch is in OFF position or negative battery cable is
disconnected when monitoring circuit resistance. Status changes on
DVOM during test procedures indicate area of fault.
TEST PROCEDURES
Intermittent Simulation
To reproduce conditions creating an intermittent fault, use
following methods:
* Lightly vibrate component
* Heat component
* Wiggle or bend wiring harness
* Spray component with water
* Remove/apply vacuum source
Monitor circuit/component voltage or resistance while
simulating intermittent. If engine is running, monitor for diagnostic
trouble codes. Use test results to identify a faulty component or
circuit.

Check the following:
* Check secondary ignition system
* Check engine vacuum
* Check fuel pressure
* Check Engine Coolant Temperature (ECT) sensor calibration
* Check Throttle Position (TP) sensor calibration
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow
* Check Idle Air Control (IAC) motor operation
* Check engine mechanical condition
* Check evaporative system
* Check EGR system
* Check coolant temperature sensor and connector
* Check Intake Air Temperature (IAT) sensor calibration
STARTS BUT STALLS
Check the following:
* Check secondary ignition system
* Check PCM power and ground circuits
* Check fuel pressure
* Check Engine Coolant Temperature (ECT) sensor calibration
* Check Throttle Position (TP) sensor calibration
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow
* Check Idle Air Control (IAC) motor operation
HESITATION OR STUMBLE
Check the following:
* Check secondary ignition system
* Check PCM power and ground circuits
* Check engine vacuum
* Check fuel pressure
* Check Engine Coolant Temperature (ECT) sensor calibration
* Check Throttle Position (TP) sensor calibration
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow
* Check oxygen sensor switching
* Check oxygen sensor heater
* Check Idle Air Control (IAC) motor operation
* Check engine mechanical condition
* Check evaporative system
* Check EGR system
* Check Intake Air Temperature (IAT) sensor calibration
* Check Park/Neutral Position (PNP) switch.
SURGING
Check the following:
* Check secondary ignition system
* Check PCM power and ground circuits
* Check engine vacuum
* Check fuel pressure
* Check Engine Coolant Temperature (ECT) sensor calibration
* Check Throttle Position (TP) sensor calibration
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow