A/C Help! (Getting hot)

IIRC, if the compressor isn't switching on, then you will get about 100 psi reading on the low side. I remember seeing my readings about that high when my compressor wasn't working.

There are two switches that can stop the compressor from engaging. One was mentioned further up(low pressure black 'canister' near firewall). The other one is between the airbox and the radiator(high pressure switch). If either of those switches is bad or corroded your compressor won't start.

For me the front switch was corroded and wiring had lost all the insulation near the switch. If the wiring looks good, unplug that high pressure switch and look inside if it's corroded clean it out. I repaired the wiring and I had to slightly bend the prongs apart to get a good contact from the plug. Mine has been working for several months. Click here for some more info

You will probably have to re-recharge the system if you bled it down and the compressor wasn't running.

Synned said:

I'm going to go try to jump the high pressure switch, the one near the radiator. How would I try to jump the switch near the firewall?

Click to expand...

The low pressure switch only has 2 wires on it purple and blue/yellow. Just connect those 2 together.

If your system pressure is really low, do not run the compressor long or it will burn up! By all means if a switch is bad, replace it, don't use a jumper wire just to get the system running again.

EDIT:Jump the wires(female) not the switch(male). BTW, when you jump the high pressure switch it takes about 5-10 seconds from the time you jump the wires until the compressor kicks on.

If you didnt have enough pressure to kick on the A/C clutch compressor (it isnt kicking on, right?) then relieving pressure probably isnt the answer. As was said, numbers need to be evaluated with the compressor engaged and engaged for a relatively decent duty cycle.


Good luck.

Because checking pressure with the clutch disengaged is pretty useless, the trick that everyone is getting at is:

If the clutch wont kick on (engage), it's very difficult to introduce fresh R134 gas (not liquid) into the system. So just to charge it back up enough to get the A/C clutch to kick-on by itself, you would have to jump the Low pressure switch terminals. Assuming the rest of the wiring is sound, this kicks the compressor on, and you can now introduce your fresh R134 into the system. Dont run the system very long with the LPS bypassed/jumped. Keep an eye on your pressures so you can know when to stop filling and unjump the LPS jumper. Now the clutch should engage on its own.

DO be real careful with refrigerant - it can freeze fingers, eyeballs, etc.

To others - I dont mean to step on toes (I REALLY hate it when others repeat what I have already posted). I rehashed some of what was already said, but it wasnt because your posts were already noticed and noted.

Now if you know pressure is good, the clutch itself could have crapped out. It has a tight tolerance (it's electomagnetically activated).
To chase the electrical side further, I would look for a drop in the 12 volt signal on its way to the clutch. Start at the A/C clutch. See if it's getting 12 volts with the A/C on. For fun, make sure it has ground too. Working backwards, I would have to check a schematic but I bet the pathway is through a WOT relay (in the CCRM IIRC). Then it goes back to the LPS. Make sure the LPS has 12 volts in and out.

Good luck bud.

IF you have juice at the LPS but not at the clutch, I would look at the WOT relay (in the CCRM).

Not sure if this will help you or not, but I just got mine back from AC work today. I did the same thing, tried jumping both switches without luck, checked for voltage at the compressor, ect ect ect. When I hooked up the charge unit, I knew it was low, but I could not get it to fill since the compressor wouldnt kick on . 138 bucks later, my AC works again. It was low on freon, and while they were at it, I had them replace all the o rings and such to eliminate a few small leaks I had. Air blows ice cold now.