What happens to the climate control unit when the blower is off?

If the Blower is off, the Recirc door defaults to the fresh air position. The Recirc door actuator is closed when a ground is applied at Pin 4 of the Climate Control PCB. When Pin 4 is open the actuator opens the door allowing fresh air to flow into the cabin.

Why is my climate control unit no longer working?

It was no longer used after 1999, due partly to unreliability, and partly due to upgrades to newer technology. The most common problems with this vintage of AC Delco climate control systems are failure of ventilation door servos, and failures of the control unit. This document pertains to the control unit.

How is the resirc door closed when the AC is on?

When Switched +12V is present the Resirc door is closed by one of the following two conditions: ( (Recirc switch depressed) or (not Defog, plus Max AC, plus AC on)). The AC Compressor control is found at the lower- right of the schematic. Pin 10 outputs +12V to drive the AC Relay.

How to repair GMC CK Series truck HVAC unit?

Use paper clips or wires to jumper across the switch connectors on the wire harness. Key on engine off, compressor clutch should “click”. If no click, check the wiring harness for open wires, functioning high pressure switch, and correct voltages. TESTING LOW PRESSURE SWITCH. With the truck running, A/C turned on.

How to repair the corvette air condition control?

03: Hold the console top plate upside down on the passenger side of the console while supporting the top plate. Remove the metal retaining clip that holds the control levers together. Now remove the screws that hold the control assembly to the top plate. Slide the temperature control lever and cable out of the control dial plate.

What should I do if my air conditioner is not working?

Check the drain by blocking it temporarily and filling the pan with fresh water—it should be gone in 30 seconds or less when you unblock the drain. After leaving the evaporator, the refrigerant, now a low-pressure gas, travels to a compressor which once again pumps it up to many times normal atmospheric pressure.

Can a heater be removed from a blend door?

If the door is stuck the heater plenum with need to be removed and the problem resolved before installing the new unit. To test the blend door operation and too double check that you are changing the correct actuator motor turn the blower motor on and work the door in each way. You will be able to feel the air change temperature or vent level.

What causes a GMC CK HVAC unit to malfunction?

This is caused by an open Switched +12V power transistor, or it could possibly be caused by a defective blower speed switch. This is caused by a shorted Switched +12V power transistor, or it could possibly be caused by a defective blower speed switch.

How to recalibrate the HVAC actuator in a GM Truck?

For manual systems it does not matter where the a/c controls are set but if you feel the need to do something, turn the blower switch on (I prefer speed 3) and set the temperature sliders about .5″ to .75″ from full cold. For auto systems, press the auto button, with the key on. Turn the ignition off.

What is the temperature control on a GMC CK truck?

Power is routed back out to Pin 7 through a 3.8 ohm resistor and the Max AC switch, but on a 1500 truck Pin 7 is not used. The Blend (temperature) door control is powered directly from +12V via Pin 5.

Why does my GMC air conditioner stop working?

For about 5 miles the A/C worked normally till we hit a R/R and the bump made it stop blowing cold air and he was finally convinced. Back to the shop and 30 min later they found the problem. Turned out to be the low pressure switch, (under hood on bottom of small tank) it was corroded and causing a loss of electrical contact.

Why is the heater on my GMC Sierra not working?

Have a 2000 gmc sierra. Heater not blowing out hot air. Both input and output hoses hot. Can air . On hot it is just blowing lukewarm air . Putting hotter. Temp gauge is registering just below 210 Could be 2 things, one would be a bad temperature valve, a plugged heater core, or a blend door actuator.

What happens to the climate control unit when the blower is off?