Radiator fan won't come on with AC

[Dukenukemx]

Just changed the condenser and recharged the AC but I noticed the condenser was hot to the touch and the radiator fan wasn't on. I tested the fan with power from the battery and it comes on, and the fan relay I tested with the battery as well. At least I think I got the correct relay tested, the second one from the right side.

Any ideas why the fan isn't coming on? It's a 90 GT 3.1.

[Stencil]

I don't believe this happens until 1994 if I recall? I don't ever remember my 89 or 92 doing this, just 94+.

Are you sure it worked before?

[Money pit Beretta]

Once again I forget.......something to do with the high pressure sensor?

[Dukenukemx]

Before I changed the condenser, the compressor wouldn't stay working unless the car moved. When the car stood still it would click on and off. It just happened that all the freon leaked out through the condenser. I didn't think to check the fan until after I changed the compressor and was glad to see it stayed on. Touched some tubing to see if it was getting cold and everything was hot to the touch. That's when I noticed the fan wasn't on.

Also, it took 12oz worth of R134a but it wouldn't take a second can, and I think my car needs 44oz?

[ifixalot]

Did you evacuate the system after you opened it up to replace the condenser?
If not, you may have moisture that froze and plugged the system causing it not to take more freon.
It should take 80% of what it calls for an R-12 charge.
Just a guess, you may be low on freon but the high side goes too high and shuts down
the compressor and then the fan.

[Dukenukemx]

Did you evacuate the system after you opened it up to replace the condenser?
If not, you may have moisture that froze and plugged the system causing it not to take more freon.
It should take 80% of what it calls for an R-12 charge.
Just a guess, you may be low on freon but the high side goes too high and shuts down
the compressor and then the fan.

I left the pump on the system for a good 30 minutes. I put R134a instead of R12, cause it's getting harder to find R12. The system is cool at first but quickly warms up. I mean the entire system is burning hot to the touch, so I doubt something would stay frozen for long. To be honest I didn't leave the system running long enough to take a second can of freon cause I was afraid I would burn something out.

Do the HVAC controls engage the fan? That maybe a place I could check.

[Cliff8928]

Pressure sensor engages the fan. If you have TWO sensors on the high-pressure line you can disconnect one of them and the fan will turn on. If you disconnect the wrong one the compressor will disengage.

[Dukenukemx]

Pressure sensor engages the fan. If you have TWO sensors on the high-pressure line you can disconnect one of them and the fan will turn on. If you disconnect the wrong one the compressor will disengage.

I'll give it a try and report back. BTW was on highway and AC works fine, so long as there's air flowing through the condenser. Stop and go traffic and it gets hot again. Radiator fan will turn on to keep the engine cool.

[Dukenukemx]

Ok Cliff8928, I disconnected one of the two pressure switches and the fan comes on and the other does stop the compressor. So i'm guessing one is the low pressure and the other is the high pressure? I should probably change both, but are they both removable?

[Cliff8928]

Yes, they just unscrew. They're on a schrader valve so you don't have to worry about it leaking. I just left mine disconnected.

[Dukenukemx]

I don't know if I like the idea of just leaving it disconnected. Kinda hard to find replacements for them. Would these replace both or am I looking at the same parts? Rockauto only lists one a/c pressure switch with the part code 22599559.

http://www.ebay.com/itm/171396952503?ss ... 1423.l2649

http://www.ebay.com/itm/351011732785?ss ... 1423.l2649

[Cliff8928]

I would suspect the cutout one is working properly. I haven't had the fan switch work right on 3 cars over the past 18 years. My GT actually has the wiring completely removed from the harness.

[Dukenukemx]

Just got the new fan switch and it works fine. It works no different than disconnecting the thing to begin with, but at least it's there. Not sure what the purpose is to not have the fan running when the A/C is on? I was able to get a AC Delco fan switch for $10 off Ebay. It was called "SWITCH Fan Blower Engine NEW Delco GM 15-2402".