A/C wiring questions.

[boostedinaz]

Im tying to fix the a/c in 1101 but have run into a problem, the a/c clutch wont kick on. I tried to fill the system and the pressure went up in the low side but started getting really high and the compressor was doing nothing. I have checked the relays and they seem to be working, I had it on full blast with the green button on etc. but the compressor wont kick on.

This leads me to a few questions. First is there a way to manually kick on the compressor? I unplugged the single wire from the compressor and applied 12 volts to it and nothing. I was gonna try the other two wires that go into the back of the compressor bit.they dont seem like they would help.

Where is the low pressure side switch? I see a switch on the line running down the driver side fender and one on the little canister with a sight glass. Is it one or the other, both, niether?

Lastly would any of the temp sensors cause an issue like this? I have a few with wires that have seen better days but not sure if that would keep the compressor from kicking on. My guess is no.

Thanks for any help. My wife is driving 1101 and shes getting upset at the 100 degree temps and black leather interior. Lol

 

[656of1000]

You ought to be able to jump the compressor relay to see if the compressor kicks on. If that doesn't work, I'd say the compressor clutch is bad.

...Something else worth checking: There is also a sensor on the evaporator, used to turn off the compressor if the evaporator is freezing over... This went bad on mine, so I just bypassed it. I wouldn't worry about freezing evaporators in 100* weather.

 

[s_firestone]

The pressure switch is on the drivers sidewall near the front. Trace back from the drier. Between the drier and ABS pump. I think you'll need to remove the coolant bottle to see the drier and lines.

Also, check the connector on top of the thermostat housing. I seem to remember that coolant temperature switch will kill the compressor if its unplugged.

 

[s_firestone]

The 2 wires that go into the back of the compressor is the low pressure switch (I think). I think the one before the drier is the high pressure switch.

 

[iceman69510]

12 volts directly to the clutch should engage it. If that does not happen, clutch is likely bad or maybe compressor is seized. Do you have 12 volts at that supply line when the a/c switch is on? If not, trace back from there.

 

[boostedinaz]

A buddy of mine let me borrow his factory manuals and I found the "official" test for checking the clutch. It failed. I'm on the look for a new A/C compressor locally and thing Driggs might be able to help.

 

[s_firestone]

Well,if you're replacing the compressor, go ahead and buy the drier and expansion valve and get it over with. Wile you're at it, go to Autozone and get a package of the r134a o-rings. They carry packages of assorted o-rings cheap. Buy a bottle of PolyEster oil (POE), not PAG. PolyEster oil is compatible with R12 and R134a so it won't react to any old residue in the new compressor.

Coat each o-ring with a layer of POE oil as you assemble lines and don't over-tighten since everything is soft aluminum.

You'll want to flush each section of the system to remove any metal debris from the bad compressor and old contaminated oil.

I did mine with brake parts cleaner and a air compressor, but they do make a flush specific for this.

If you do not have a vacuum pump go rent one. Otherwise you'll never get all the water vapor out.

Don't crack open the seals on the new drier until everything else is done, it should be the last part you put on right before you apply a high vacuum to let the water boil out. Driers only hold about a 1/2 teaspoon of water new.

 

[656of1000]

^^^
+1

If you're going to all of the trouble of replacing the compressor, you gotta do it right. The results will be very worthwhile.

 

[toybreaker]

Quoting s_firestone:
excellent advice



One addition to that post might be to pull the system into vacuum with the old receiver/dryer and leave it evacuated overnight before installing the new receiver/dryer.

It will prevent "most" cases of having to re-open the system.

At the very least it will remove all the moisture that is in the system as it sits and this will decrease the amount of moisture in the system the new unit will have to deal with.

 

[boostedinaz]

Blah.

So Brian got me his old compressor and after installing and testing, his compressor works. I decided to change out the dryer and O rings as well but decided against the changing the evaporator cause I didn't want to get that much into it. The down side is that when I was rushing to finish the install at 11:30 last night (should have slowed down I know I know) I muched one of the hard line ends. /ubbthreads/images/graemlins/banghead.gif Now I am on the look out for one and it seems that Toybreaker might be my saving grace.

I'll try and keep this updated when I get the line and charge the system.

 

[boostedinaz]

Heading out to a junk yard today to with another GVR4 owner and looking for a hard line. They say they have a 92 Galant but don't know whats still left on it or what trim package it is. Hopefully it works out and I'm back to having A/C. If not at least it will be a fun day.

 

[boostedinaz]

Finally!!! Got the line and a few other parts 1101 needed. Installed pretty much everything I bought and booya AC works. Thanks for all the help guys.

 

[s_firestone]

Cool!! /ubbthreads/images/graemlins/wink.gif

 

[iceman69510]

I managed to get mine fixed last year (late) and sure appreciate it. Even found a bottle of R12 and was able to charge mine with that (bartered some 134a for it).

 

[boostedinaz]

Wife drove it all day today and said it worked great. I also rebuilt the power steering pump tonight so hopefully it will be 100% leak free as well.

I should update by build thread with the detailed info.