2004 AC control panel problem

[Jim&MaryJo]

On my 2004, the ac control panel -- I believe the fan switch -- developed an intermittent failure causing the fan to shut off.

I pulled some panels to get partial accesss and was able to duplicate the problem by moving a wire or pneumatic bundle leading to the area of the fan switch. I think it's an electrical "open".

Panel looks like a GM OEM part. Getting ready to pull all the panels to gain full access.

Anyone experience this and fix or know a source/part# for the panel?

Thanks!

[dgerstel]

Jim,

I would make sure that the problem is actually in the panel. If you need a panel, here is where WRV was getting the dash air system.

Acme Radiator & Air Conditioning, Inc.

[Jim&MaryJo]

Thanks very much Dale!

[Jim&MaryJo]

The control panel is a Delco part# 16238475.
It should be possible to order individual components of the control panel from an auto parts distributor, using this part# as a reference.
This should be the same control panel for 03-06 models, maybe more of the years.
Great tech support contact at Acme is John @ 913-371-5373.

[jetar]

I have had the same problem on my 01. I pulled the panel and went in behind with my hand and secured the connections by pushing them in. It seemed to work and I believe in my case it is vibration causing a loose connection. Good luck

[Chuck Thomas]

I have a related issue involving the AC/Heater blower motor. Mine is occasionally vibrating (the shaft vibrates in the bearing housing) sometimes, particularly when it is cold and first starts up. I fear that ai will have to replace the motor/bearing assy soon. Has anyone done this themselves? Is this an easy repair or should I take it into a shop and have it done? Anyone who has replaced the motor assy: I would appreciate your input on this matter.

[Old Scout]

Not sure the noise you are describing is the fan bearing--there is a noise [mostly at start-up] caused by an air/electically-driven air damper that changes airflow from inside/outside or from upper/lower/defrost air vents--I think....

[dgerstel]

Old Scout,

I am quite sure that the noise you are referring to is from the vacuum pump, used to power the dash AC and heating system. Diesels do not produce a vacuum like gas engines do and a vacuum pump is required to do so. See pump on bottom of page from link.

Acme Radiator & Air Conditioning

This pump will always run long enough to build up a vacuum on start up and then shuts off. While driving you can't hear it, only while stopped is it noticeable. It is mounted on the outside of the "fire wall" (wall in front of drivers feet.) in front of the driver.

[Rick J Fisher]

Thanks Dale for suggesting that the terrible noise was the vacuum pump and not a fan. However mine does not seem to shut down in a reasonable time. While looking for a leak, I tugged the tubes connected to the control and the yellow one came loose. The clear plastic connector was a loose fit. I trimmed it and re-attached it. Still very loose. I am not sure that was the leak because I plugged the nipple with my finger and the pump kept running. Is there an easy way to access the back of the control? If that pump could be insulated from the panel, it probably would not make so much noise but it should run only for short bursts when a control is changed.

BTW shouldn't that hydraulic fan motor last longer than a year?

[dgerstel]

Rick,

The vacuum pump is controlled by a built-in pressure switch, so that the pump only runs long enough to keep a specified vacuum (when the ignition is on.) The switch on ours will not turn the pump off at high elevations. If yours won't shut off, I would look for another leak.

As to fan motor, yes it should.

[Jim&MaryJo]

Just a follow-up to my problem.
Jetar was right! Thank you.

The connector to the fan switch was not latched in. I had tried to re-seat it, but the latching mechanism (which I could see on the replacement control head I bought) required I push from the back and "counter-push" from the front to get it to snap in properly.

A good clue... with power on, the connector was warm.

[Chuck Thomas]

This is a fan motor issue. I can change the fan speed to high when the chatter is occurring and it will stop immediately. Has anyone reading this post changed out the dash AC fan motor themselves? If so, I would like to hear from you. My email is cathomas6@gmail.com

[Rick J Fisher]

Finally solved the problem of a continously running vacuum pump. Most of the tube connections to the control valve were loose. I removed the radio above the controller for better access. I used four six penny nails to release the clips. The control panel is held in by three nylon wire ties. After clipping these I was able to maneuver the panel so I could acess the back through the radio hole. The tube connection is held on by three clips. Releasing these allowed the manifod to come loose and give me easy access to the tubes. I used a small nylon tie around each tube to compress it before pushing it on its nipple. One at a time because there is no color code. Now the pump shuts off after about 30 seconds and only burps when a control is changed. I was able to replace two of the ties to secure the panel but that is enough.

[EngineerMike]

If your vacuum pump doesn't shut off, or you feel it runs too much, there are tube connections at the pump/accumulator-tank itself as well as at the control panel. Pump is located under the lower corner of the windshield, DS, accessible with the gen slide out. As a first check, since this is easier than dash disassembly, I'd start @ the pump.