Dodge Ram Truck 1500-2500-3500. Manual - part 1490

HEATER - INTAKE AIR

DESCRIPTION

The intake manifold air heater element assembly is located in the top of the intake manifold.

OPERATION

The air heater elements are used to heat incoming air to the intake manifold. This is done to help engine starting
and improve driveability with cool or cold outside temperatures.

Electrical supply for the 2 air heater elements is controlled by the Engine Control Module (ECM) through the 2 air
heater relays. Refer to Intake Manifold Air Heater Relays for more information.

Two heavy-duty cables connect the 2 air heater elements to the 2 air heater relays. Each of these cables will supply
approximately 95 amps at 12 volts to an individual heating element within the heater block assembly.

CAUTION: The heater elements are no longer grounded using an external ground strap. Grounding is now
accomplished using two electrically conductive gaskets. Failure to use these gaskets will result in faulty
heater element operation.

Refer to the Powertrain Diagnostic Procedures manual for electrical operation and complete description of the intake
heaters, including pre-heat and post-heat cycles.

REMOVAL

If servicing either of the heater elements, the entire
block/element assembly must be replaced.

1. Disconnect both negative battery cables at both

batteries. Cover and isolate ends of both cables.

2. Remove both the intake manifold air intake tube

(above injection pump), and its rubber connector
hose (2).

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3. Lift 2 rubber covers (3) to gain access to 2 positive

(+) cable nuts.

Remove two cable nuts (6) and remove 2 cables

from studs.

5. Remove wiring harness clips.

6. Remove engine oil dipstick tube bracket from air

inlet connection and fuel filter housing.

7. Remove four housing mounting bolts (1) and

remove heater element assembly.

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INSTALLATION

If servicing either of the heater elements, the entire block/element assembly must be replaced.

1. Using 2 new gaskets, position element assembly and air housing to intake manifold.

2. Install 4 housing bolts and tighten to 24 N·m (18 ft. lbs.) torque.

3. Connect 2 positive (+) heater cables at cable mounting studs. Do not allow either of the cable eyelets to

contact any other metal source other than the cable nuts/studs.

4. Install engine oil dipstick tube and mounting bolt.

5. Connect rubber connector hose and intake tube to air intake housing. Tighten clamp bolts to 11 N·m (100 in. lbs.)

torque.

6. Connect both negative battery cables at both batteries.

RELAY - INTAKE AIR HEATER

DESCRIPTION

The two intake manifold air heater relays (4) are
located in the engine compartment. They are attached
to a common bracket. This bracket is attached to the
right battery tray.

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OPERATION

The Engine Control Module (ECM) operates the 2 heating elements through the 2 intake manifold air heater relays.

Refer to Powertrain Diagnostic Procedures for an electrical operation and complete description of the intake heaters,
including pre-heat and post-heat cycles.

REMOVAL

The two intake manifold air heater relays (4) are
located in the engine compartment. They are attached
to a common bracket. This bracket is attached to the
right battery tray.

The mounting bracket and both relays are replaced as
an assembly.

1. Disconnect both negative battery cables at both

batteries.

2. Disconnect four relay trigger wires at both relays.

Note position of wiring before removing.

3. Lift four rubber shields from all 4 cables.

4. Remove four nuts at cable connectors. Note posi-

tion of wiring before removing.

5. Remove relay mounting bracket bolts and remove

relay assembly.

INSTALLATION

1. Install relay assembly to battery tray. Tighten mounting bolts to 4.5 N·m (40 in. lbs.) torque.

2. Connect eight electrical connectors to relays.

3. Connect battery cables to both batteries.

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