2007 9200i ac issues

[race7820000]

I have a 2007 9200i day cab that the air conditioning quit working .

It stopped last week and I checked pressures which were fine. Pressed a.c. button with key on and couldn't hear the clutch engage so I put a test light on wire that goes into compresser and it had no power.

Swapped relays which I found 2 that are associated with the ac and nothing. Pressed the breaker fuse and it clicked and the ac started working again!!!

Next day it stopped again, pressing the fuse did nothing, swapping relays did nothing. I foind the fan switch on the system but i cant find the low or high pressure switch .

I'm assuming something got hot and tripped the fuse. I looked everywhere I could and tore apart dash and looked at what I could yo try and find a short.

It still doesn't have power going to compresser. When u press the ac button on dash both the relays click but that's it.

If you run power to the compresser from the battery it works and cools like it should.

I'm lost. Any ideas?

[smorgan87]

Assuming it has the same clusterf $%& body cotroller ac system as the prostar which is faulting out for no good reason. Theres a fuse that powers the hvac body controller unplug it for a few seconds and plug it back in. Or rawze has a contraption that replaces the body controller for hvac functions. Lemme find the link

[smorgan87]

http://rawze.com/forums/showthread.php?t...1#pid15791
Assuming its the same as the prostar.

[race7820000]

My system is different than you described.

It has low and high pressure switches under the floor .
When you unplug the low pressure switch the ac works. While it is unplugged if you use a jumper wire and jump the pigtail the ac clutch becomes disengaged ...

So I'm assuming the low pressure switch is bad?

[smorgan87]

Replace the pressure switch

[smorgan87]

If its an on off swtich you can double check your pressure with it jumpered to engage the compressor and ohm out the switch to see if it works. Also check for any corrosion and make sure the connectors are snug.

[smorgan87]

Or as long as you dont have a leak you can keep it jumpered. Just make damn sure you dont run er empty.

[race7820000]

The compressor will only come on of you unplug the pressure switch.

If u run a jumper wire to the plug the compresser stops.

Everything I've tried to look up says the compresser should come on with the jumper wire. Not just having the plug sitting by itself

[smorgan87]

Im afraid im not gonna be able to help you without seeing it, metering everything and having a diagram to look at. Good luck. They can be rewired to work like old systems did. High side psi sensor cuts the fan on and off, low psi cuts off the compressor. Knobs turn on the blower and operate the blend doors. Good times.