ac issues, what needs to be replaced

[xtech210]

so im in texas, weather here sucks during summer. i got a reman compressor to replace the one that was in the car (91 legacy L wagon, dcw17 compressor). got everything hooked up, pulled a vacuum, held at 29.5 for over an hour after we disconnected it.

replaced all the gaskets before hand, as well as the dryer filter.

hooked up gauges, can o freon, turned car on and ac on high, nothing. waited 10 minutes, can still had freon in it. made sure clutch wasnt seized, can of freon had been pierced and was indeed open.

decided to jumper the compressor and make sure its actually working. hooked it up to a switch that we wired to the battery, flipped it, compressor kicked on and sucked in the freon, ac proceeded to get cold.

what do i need to look for to find out why the compressor wont engage when hooked up the way its supposed to be?

-edit-

i have alldata 2014 and am attempting to make sense of this, so if there's something specific in there i should look for, im all ears. this is my first (and last) time doing ac work. i can see why they charge so damn much now.

[Legacy777]

This is a very basic AC schematic

http://main.experiencetherave.com/subar ... ngdiag.jpg

Is the pressure switch on the dryer hooked up? If pressure is not registering above a certain point that will keep the compressor from kicking on. I'd recommend checking the fuses to the system as well.

You can find more detailed AC wiring diagrams on page 38 & 39 of 82 in these wiring diagrams.

http://main.experiencetherave.com/subar ... agrams.zip

[xtech210]

yeah the pressure switch on the dryer is hooked up. any way i can test if its good or not?

are the only fuses for the AC on the relay panel under the hood, or is there one located under the dash as well?

its raining outside, bad, so dont wanna go outside til later . any info is appreciated!

[xtech210]

alright, so i went back to my scooby mech and we did a bunch of testing. we confirmed the AC does indeed work and that the radiator fan and aux fan both come on when the engine reaches a certain temp and the AC is engaged manually.

determined that either the pressure switch or the HVAC controls inside the cabin are bad.

is there any way to determine which it is so i can just get one part and not both?

[Legacy777]

Did you look at this particular wiring diagram?

http://main.experiencetherave.com/subar ... g_Diag.pdf

If you go to the bottom of the second page you will see the pressure switch. There is however a discrepancy in the factory manual regarding which pins do what. The diagram I linked to above is showing pins 1 & 2 operate the pressure switch while pins 3 & 4 operate the fan control. However another part of the manual indicates that is backwards. So you'll need to try and test each set of pins to see which ones turn on the radiator fans. You'll want to jumper pins 1 & 2 and pins 3 & 4 on the chassis side harness to see which set of pins turns the radiator fans on (key needs to be in the ON position). The other set of pins will be the pressure switch. Try jumper those pins to see if the AC clutch will turn on.

If it does, then you can check the resistance of the pressure switch pins to see if there is continuity. You should have continuity when there is about 30 psig in the AC system.

[xtech210]

we jumpered one set and the fans came on. we jumpered the second set and nothing happened. would this indicate a bad pressure switch?

[Legacy777]

No, that would indicate something else is wrong. You can verify that the pressure switch is working by checking the resistance across the corresponding pins on the pressure switch to see if they have continuity (0 ohms). If they do then the switch is working ok.

Let me see if I can scan the troubleshooting flow chart later today which walks you through specific steps when the clutch won't engage. Before that I would recommend checking all the fuses and relays associated with the AC system. They should be located in the fuse box in the engine bay. This diagram lists the specific fuse numbers:

http://main.experiencetherave.com/subar ... ngdiag.jpg

These scans list each fuse number and what they are for:

http://main.experiencetherave.com/subar ... ns/118.jpg
http://main.experiencetherave.com/subar ... ns/119.jpg

[xtech210]

thank you so much, im still making sense of all this but its coming together. we checked (and replaced just in case) all the relays under the hood. checked ALL the fuses under there. before i had replaced the AC compressor, i did notice the AC fuse was blown. replaced it weeks ago but checked it again, fuse is fine.

do any of the fuses under the dash have anything to do with the AC? take your time, i have all weekend to work on this. i will jumper the high pressure switch one more time with the diagrams you provided and see if i can get the clutch to engage.

[Legacy777]

Here is the AC clutch diagnosis flow diagram that walks through each step to troubleshoot and diagnose the problem.

http://main.experiencetherave.com/subar ... iagram.pdf

Let us know what you find out.