Still having problems with my AC as described in a previous post. Basically the compressor turns on whenever it wants to. Sometimes I can turn it off with the AC button, most times I cannot.
Now that it is Fall in Texas, I am wanting to disconnect the AC. I removed the connection in the posted picture and it shut the AC off.

My question is.... Did i disconnect an appropriate connection? Will this be OK to be disconnected for Fall and Winter and then I will reconnect next summer.
I sealed off the connection with HVAC metal tape and it seems to be holding.
Just wanted to make sure disconnecting this is OK and/or is there a better solution? fuse?

Thank you in advance for your help.

 

That should do it. Let us know when your ready to diagnose the problem further.


George

 

One thing to consider is that the AC should be cycling anytime the defrost is selected as well as the AC settings. If it's turning on and off randomly without changing the settings that's an electrical issue you probably want to solve.

Also another consideration is when the AC cycles it moves oil through the system which conditions all the seals. Letting the AC system sit for an extended time without cycling risks those seals drying out and leaking freon.

 

Just to add on, the plug you disconnected is the power for the AC compressor clutch. This will prevent the compressor from trying to turn on. Another option would have been to simply remove the AC fuse from the fuse panel.

 

Sorry for the delay in updating information for this problem. I was gathering more data and then life threw a few curveballs.
So, back in November, disconnecting the ac did stop the ac from coming on all by itself, but the heat started coming on by itself.
I think it was coming on with the ac because it would get hot first real quick then ac cold.
Later that month I was driving during a beautiful 61 degree day and the heat came on. it felt like it was max heat.
I had no control with the HVAC controls. Fan did nothing, heat did nothing, face/foot/mix did nothing.
Then I stopped for gas and when I turned the car back on it was off.
The next morning it was 40 and I couldn't get the heat to come on at all, figures!
Since then the heat has not come on and the HVAC panel does nothing. I included a HVAC panel picture.
Do you think this is enough information to diagnose the problem do I have to replace that HVAC panel?
I like to do my own repairs, but I am definitely not a mechanic. If that is the recommended repair, where do you recommend I get the part.
I am guessing there is a computer board in there behind that panel that has given up working?
Thank you in advance for your help with this.

 

I cant make out that picture. Is this manual or automatic HVAC?

George

 

sorry for the lousy picture, is this better?

 

You have the automatic HVAC option. This system is actually quite complicated so there are many things that can be going wrong. Sensor inputs, multiple control modules, electric solenoids, class 2 digital data bus instructions, etc. The easiest part of this to diagnose is probably the AC compressor not turning off. The air vent issue is more complicated. In this simplified diagram, the HVAC module sends an analog request for AC compressor to the high pressure switch on the compressor then on to the VCM then on to the compressor relay then power is applied to the compressor when the relay turns on. The question is where in this chain is constant power being applied? The possibilities are:

The HVAC module (ECCM)
The VCM
Stuck relay
Short to power somewhere along the way.




If you have a digital multimeter and know how to use it I can help you confirm what has failed. The HVAC module is a prime candidate but only proper testing can confirm for certain. Let me know if I can help.

George

 

Thank you George,
I do have a digital multimeter and I am willing to test what ever you suggest so thank you for offering.
Please keep in mind that even though I disconnected the ac the whole module is dead now.
originally it looked like an ac problem that is why I disconnected it, but heat was coming out briefly before ac
After disconnecting ac it was putting out heat only, now nothing works.
I also have a fluke 30 clamp meter if that helps and a OBD code reader if needed
thanks again what is step number one?

 

What do you mean by dead? No function, no lights, nothing changes when ***** are turned?

Also, what happens if you reconnect the AC compressor, does it still run 100% of the time?


George