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I need assistance on a 1995 gmc top kick 3116 intake heater…

I need assistance on...

I need assistance on a 1995 gmc top kick 3116 intake heater not working

Mechanic's Assistant: What is the complete model and serial number of your machine?

Ser 9gk21087

Mechanic's Assistant: Are you fixing this yourself? What have you tried so far?

Yes, replaced module on driver side and relay by heater does not click on, if i power probe power it kicks on

Mechanic's Assistant: Anything else you want the equipment mechanic to know before I connect you?

I know the coolant temp is part of system but im not sure which sensor

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Answered in 1 hour by:
1/17/2018
Daniel Wilson
Category: Medium and Heavy Trucks
Satisfied Customers: 6,884
Experience: Owner at DJ Wilson
Verified

Hi ,My name is***** will be glad to help. We can follow up as needed on here, Give me some time to review your information and post my responses. Im not an employee of the site but I help on here as time allows in between jobs. Response time will vary depending on my work load , etc.

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Inlet Air Heater

To aid starting and prevent white smoke emission at start up, the Caterpillar 3114/3116 Diesel Truck Engines are equipped with an electric heater located at the air inlet casting. Under the proper conditions of jacket water temperature, oil pressure, ignition position, and elapsed time, an electronic control module switches the heater system on. The system is capable of delivering heat for thirty seconds prior to start up, during cranking, and up to ten continuous minutes, followed by ten minutes of on/off cycling after the engine has started.

If for any reason the inlet air heater system malfunctions, the engine will still start and run. The only concerns may be the amount of "white smoke" present and the possible need to use an alternative starting aid.

System Components

The basic components of the inlet air heater system are: magnetic switch, heater element, coolant temperature switch, electronic control module, oil pressure switch, and an indicator lamp.

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Customer reply replied 6 months ago
We know that
What to do we look at based on what I originally sent that i ddid and solenoid not kicking on to turn on intake heater??

The magnetic switch (3) is located on the inlet manifold cover. It turns the 12 V heater ON and OFF in response to signals from heater control module (9).

The inlet air heater (4) is located on the inlet manifold cover (1). The heater element has a ground strap (6) that must be connected to the engine.

The coolant temperature switch (8) is located in the temperature regulator housing (7). In order to activate the system, the coolant temperature must have dropped below the lower limit of the switch. Above the upper limit, the switch is open, and the inlet air heater system will not function. Between the lower and upper temperature limits, the switch may be open or closed. The heater control module (9) is mounted on the air cleaner bracket above the engine. The heater control module requires input from the oil pressure switch (11) and coolant temperature switch (8) to control the heating cycle of the heater element.

The oil pressure switch (11) is located in the oil manifold (10). The switch is normally open below 240 ± 70 kPa (35 ± 10 psi). Above the limit, the switch closes, indicating to the control module that the engine is running. The indicator lamp is located in the light cluster on the instrument panel of the vehicle. It has an amber lens and informs the operator when the system is active.

Lamp Test

When the ignition switch is turned to the "RUN" position, the control module energizes the magnetic switch, supplying the heater element with power for two seconds. The indicator lamp in the instrument panel should illuminate at that time. Failure of the lamp to illuminate indicates a system malfunction.

NOTE: If the coolant temperature is below the lower limit of the temperature switch, the system should go directly from the lamp test into the pre-heat cycle (light will not turn off).

Pre-Heat Cycle

Three conditions must exist before the inlet air heater will operate in the pre-heat cycle:

1. The ignition switch must be in the "RUN" position.

2. The coolant temperature is below the lower limit of the temperature switch.

3. The inlet air heater has not timed out for thirty seconds in the pre-heat cycle.

There are three ways to end the pre-heat cycle:

1. The ignition switch is turned to the "START" position.

2. The ignition switch is turned to the "OFF" position.

3. The system reaches the thirty second time limit.

Crank Heat Cycle

Three conditions must exist before the inlet air heater will operate in the crank heat cycle:

1. The ignition switch is in the "START" position.

2. The thirty second timer starts when the ignition switch is turned to the "START" position and continues with the engine not running, and the engine in the "RUN" position. It is continually reset as long as the ignition remains in the "START" position.

3. The coolant temperature is below the lower limit of the temperature switch.

There are three ways to end the crank heat cycle:

1. The ignition switch is turned to the "OFF" position.

2. The engine starts.

3. The system reaches the thirty second time limit with the ignition in the "RUN" position and the engine not operating. Crank heat will resume when the engine is returned to the "START" position.

Post Heat Cycle

Four conditions must exist before the inlet air heater will operate in the post heat cycle:

1. The ignition switch must be in the "RUN" position.

2. The coolant temperature is below the upper limit of the temperature switch.

3. The engine oil pressure is above 240 ± 70 kPa (35 ± 10 psi).

4. The inlet air heater has not timed out for ten minutes in the post heat cycle.

There are four ways to end the post heat cycle:

1. The ignition switch is turned to the "OFF" position. When the switch is turned to the "OFF" position, the regular heat cycle is terminated.

2. The engine stalls.

3. The coolant temperature exceeds the upper limit of the temperature switch.

4. The system reaches its ten minute time limit.

Cycle Heat Cycle

Four conditions must exist before the inlet air heater will operate in the cycle heater cycle:

1. The ignition switch must be in the "RUN" position.

2. The coolant temperature is below the upper limit of the temperature switch.

3. The engine oil pressure is above 240 ± 70 kPa (35 ± 10 psi).

4. The inlet air heater has timed out for ten minutes in the post heat cycle.

There are four ways to end the cycle heater cycle:

1. The ignition switch is turned to the "OFF" position. When the switch is turned to the "OFF" position, the cycle heater cycle is terminated.

2. The engine stalls.

3. The coolant temperature exceeds the upper limit of the temperature switch.

4. The system reaches its ten minute time limit

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Click this link for the diagram for the circuit to help.

Service info

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Customer reply replied 6 months ago
WHICH IS COOLANT SENSOR, THERE IS 2 IN SAME SPOT
Customer reply replied 6 months ago
IS IT BEST TO JUMP THE SENSOR WITH PAPERCLIP TO ELIMINATE IF OIL OR COOLANT SENSOR CAUSING ISSUE?ON THE MODULE THERE SIX WIRES, WHICH ONES TO VERIFY POWER TO MAKE SURE THATS GETTING WHAT IT NEEDS?

Yes you can jump the switches for testing one at a time . this will help determine a switch issue but check the wiring harness as well.

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As you can see in the diagram terminal D runs through the power relay and the power relay should have power waiting there for the module to send signal out of D to trigger the power relay to energize the heater.

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The power relay gets ground from the module so if you grounded the relay for test purposes and power is there from the breaker, it should send power to the heater.

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Im logging out for a while but let me know if you need more help.

Please take a moment to rate as that is how the site credits my time helping on the site or let me know if you need more help. 5 star and bonuses are always greatly appreciated.

Daniel Wilson
Category: Medium and Heavy Trucks
Satisfied Customers: 6,884
Experience: Owner at DJ Wilson
Verified
Daniel Wilson and 87 other Medium and Heavy Trucks Specialists are ready to help you
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Customer reply replied 6 months ago
can you get a wiring schematic for the taillights, i have no reverse lights and cant find the wiring online

Hi Joe. Mine go back to 98/99 on chassis but if you open a new question there might be someone on here that might have them for your 1995.

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