A.c. compressor non stop runs

[Albert]

With compressor running pulled switch off suction accumulator and compressor continued to run. What do u mean by with the key off you mean with the truck not running? I'm not sure if there is an orfice I would think these trucks would have an orfice.

 

[J_lope82]

Sounds like a bad control module or a short on the circuit controlling the compressor clutch relay.

 

[delta_p]

With compressor running pulled switch off suction accumulator and compressor continued to run. What do u mean by with the key off you mean with the truck not running? I'm not sure if there is an orfice I would think these trucks would have an orfice.

yes when you key off the truck that is running.

Since everything appears to be working and you can't even turn off the compressor with the ac switch in the truck, I agree with Jlope82, sounds like a short or bad module.

For reference the cycle switch and the compressor high pressure cutoff switch are in series and go the VCM to tell the VCM to interrupt or not the ground path to the clutch relay coil, turning on/off the clutch. The high pressure cutout switch is normally closed and probably never cycles in its life. its there so the compressor doesn't pump its guts out onto the road because of the charge being too high or completely blocked path. By chance can you measure the idle pressure of the charge with the truck sitting and not having run for a while. how much higher than 50 Psi it?

 

[Albert]

Yea I've been doing some reading on the same issue I have an it seems like a bad vcm. This is ridiculous never had this Many issues before on a vehicle I've ever owned. I've head you can get the vcm reasonable but then you have to take it to a dealer for them to program it?

 

[df2x4]

Yea I've been doing some reading on the same issue I have an it seems like a bad vcm. This is ridiculous never had this Many issues before on a vehicle I've ever owned. I've head you can get the vcm reasonable but then you have to take it to a dealer for them to program it?

If you're going to go that route, have someone like Black Bear Performance do the reprogramming for you. No point in paying a dealer the same amount of money for a stock tune.

 

[DerekTheGreat]

You try just replacing that relay? Might be a dumb idea but as I like to say, simple things first...

 

[Albert]

Yes as stated above early in post I have replaced relay. Now what kind of vcm should I use can I use one from a 97? There's a guy parting out a truck that's a 97 with 4wd sane motor could I use that vcm or should I just buy new?

 

[df2x4]

Yes as stated above early in post I have replaced relay. Now what kind of vcm should I use can I use one from a 97? There's a guy parting out a truck that's a 97 with 4wd sane motor could I use that vcm or should I just buy new?

Black Bear sells spares for $50 IIRC if you buy a tune from them.

 

[DerekTheGreat]

I see that you swapped relays.. Is this a new problem or has it always been there? If you wire up the relay wrong or put it in wrong you can what you've got going on. I put my horn relay in wrong for my Town Car and couldn't figure out why the horn kept blaring, thought it was the switch in the steering wheel when it turned out I put the relay in backward.

 

[Albert]

I've tried putting the relay in different no matter what position I place the relay in the compressor still runs I'm gonna email black bear to see what there pricing is on a tune I guess I should go with a little bit of an aftermarket tune?