Common questions

How does a defroster work on a GMC Truck?

How does a defroster work on a GMC Truck?

Line up the heater/defroster valve lever with the mode actuator cam slot. Line up the A/C valve lever with the mode actuator cam. 2. Install the mode actuator mounting screws to the HVAC module. Tighten the screws to 1.6 N·m (14 lb in). 3. Connect the electrical connection at the mode actuator (10). 4. Install the Body Control Module.

What to do if your GM fan won’t defrost?

See if this fixes the problem. Many of GM’s AC control heads have a built in reset feature that when power is removed and then applied it will go through a cycle that activates all the vent doors and mode doors. It’s worth a try.

What to do if your defrost is not working?

Place the ignition switch to the OFF position. Remove the HVAC/ECAS fuse for a minimum of 10 seconds. Install the HVAC/ECAS fuse. Start the vehicle. Wait 40 seconds for the HVAC control module to self-calibrate. Verify that no DTCs have set as current DTCs.

Is the Astro fan only blows defrost?

Re: Fan Only Blows Defrost, Won’t Change To Floor Or Vent. Yea the problem with them astro’s is the way the damn motor is crammed into the dog house with the heat it destroys the hard plastic vacume line . I have had 5 of them and every one had this problem until you change them out with rubber lines .

Line up the heater/defroster valve lever with the mode actuator cam slot. Line up the A/C valve lever with the mode actuator cam. 2. Install the mode actuator mounting screws to the HVAC module. Tighten the screws to 1.6 N·m (14 lb in). 3. Connect the electrical connection at the mode actuator (10). 4. Install the Body Control Module.

See if this fixes the problem. Many of GM’s AC control heads have a built in reset feature that when power is removed and then applied it will go through a cycle that activates all the vent doors and mode doors. It’s worth a try.

What are the codes on a 2004 Chevy Silverado?

This 2004 Chevrolet Silverado came in with the complaint that the air only blows through the defrost and will not blow out of any other location. There were codes B0263 and B3770 stored in the HVAC module. The codes refer to mode actuator faults. To access the actuator, the driver’s side heater floor vent extension has to be removed.

Where is the mode actuator on a Chevy Silverado?

The codes refer to mode actuator faults. To access the actuator, the driver’s side heater floor vent extension has to be removed. There is a single push pin that holds it on. With the push pin removed from the vehicle the vent extension can be dropped down and pulled off of the main heater- a/c case.

This 2004 Chevrolet Silverado came in with the complaint that the air only blows through the defrost and will not blow out of any other location. There were codes B0263 and B3770 stored in the HVAC module. The codes refer to mode actuator faults. To access the actuator, the driver’s side heater floor vent extension has to be removed.

How to change the mode actuator on a 2003 Chevy Silverado?

This repair of course should be generally the same for 2003 through 2007 Classic series trucks and suvs. Remember to preset the controls to the split defrost / floor position before removing the old actuator. If needed, use a small screwdriver or the edge of a quarter to rotate the actuator into the correct position.

How to change the mode of a Chevy Silverado?

The control head therefore must apply a ground on the tan wire to reduce the voltage to zero to command clockwise rotation. It must also apply voltage to bring the reading to 5 volts in order to command counter clockwise rotation. All voltages referred to above should be considered nominal volts.

How is the AC system on a ram truck?

New RAM AC systems appear to be entirely dependent on an electronically-controlled blend door. Whereas, previous gen vehicles also had a heater core valve that helped ensure the truck’s heater core was not bleeding too much heat into the AC system vents/airflow.

Why is my a / C compressor leaking oil or refrigerant?

Contrary to popular belief, refrigerant is not consumed by using the air conditioning. The most common source of lost refrigerant or oil in a functioning, leak-free system is at the compressor shaft seal. This is typically the result of cars and trucks that aren’t driven on a daily basis and/or…

Author Image
Ruth Doyle