Did Paper Clip test on A/C... Where do I go from here? Also, will pay member to fix.

[micronp450]

Hey fellas,

I have a 1992 SHO MTX with 150K miles. She runs perfect but it is starting to get hot here and I can't be without A/C for another year. :sun:

I ran the paper clip test tonight. I pulled out the pressure sensor connector out of the mini propane tank looking part by the battery and radiator. Put both ends of the paper clip into the plug (Female Side) and the clutch does not spin. When I did put the paper clip in I did hear the RPM's go lower like there was more load on the car but like I said it did not engage and start spinning.

So where do I go from here? I hate to throw away the car just because the A/C isn't working especially since everything else runs pristine. Can someone provide me with a list of parts that I should get to refresh the system? I'd say the paper clip test shows that the compressor is on top of that list. Also, where could I get the parts for a resonable price. Willing to support our vendors. Also, anyone in my area be willing ot work on that and a few other things on the car? I am in Central Jersey by Six Flags Great Adventure in Freehold.

Thanks a bunch.

 

[Wakeboy1337]

Try to give the A/c Clutch 12 volts on the connector on the compressor. better yet, do the pin test but put a volt meter on the a/c compressor clutch wire.

 

[micronp450]

Thanks for the quick response. I'll try this tomorrow. Sorry for my lack of knowledge but what will this tell me? Just trying to learn here.

Thanks

 

[Wakeboy1337]

It will tell you that the Clutch is getting the voltage to engage. If it is getting voltage there, then its time for a new compressor with clutch.

 

[rubydist]

My last 95 had a wiring problem between the ccrm and the a/c clutch - the ccrm had voltage telling the clutch to run, but the voltage never made it to the a/c clutch. a little rewiring solved the problem.
that is why you want to check at the a/c clutch to see if it is getting voltage.

 

[micronp450]

Ok - Will try it shortly.

 

[micronp450]

I am under the hood right now. I see the plug going into the compressor. Under the jacket I see it has two wires. Do I unplug it an attach the voltmeter to the plug side while the car is running?

 

[Wakeboy1337]

put the volt meter into the wires and see if it is getting 12 volts. whle you do the paper clip test with max a/c on

 

[micronp450]

Ok I will clamp the voltmeter onto both wires and try it

 

[micronp450]

Ok I had to pull the connector out since it was a pain to get to it plugged in. I verified volt meter by putting the red on the battery and got 14.9 volts. I unplugged the connector on the front of the compressor and stuck the VM into the plug and get 14 volts. Seems like it is indeed the compressor. Is there any other parts I should order besides the compressor?

Thanks for the help

 

[32MTX]

first try a new compressor clutch, it could be broken

there is probably nothing wrong with the compressor at all........

I think there is a nut on the compressor, its either 7/16 or 12mm, probably 12mm since its a Denso compressor, and see if it turns clockwise...... it should turn, if its locked up you need a compressor. If its not locked up you most likely need just a clutch, its like 30 or 40 bucks.... common problem on SHO's for some reason I think.... I've had 2 fail on two different SHO's

 

[93rev2sev]

Take the belt off and see if you can turn the compressor by hand.

 

[hawkeye18]

did you try whacking the compressor clutch face with a broom stick while the "propane tank" sensor was shorted? It could be just that the clutch needs re-shimming. That happens pretty often. If it magically turns on when you poke at it with a broom, the clutch is out of tolerance.

 

[rubydist]

measure the resistance across the a/c clutch coil - it should be around 3-4 ohms. if its a lot, that means the clutch coil is open and needs replaced. if its 0, that means its shorted and needs replaced. if its 3-4 ohms, then that means you need to adjust the clutch gap so it pulls in.

 

[micronp450]

93rev2sev/32MTX,

When I was doing this I did try to spin the wheel while the belt was on. Of course it wasen't engaged but I was able to turn it easily. I don't know if that tells you the same thing.

hawkeye18,

I will try that this weekend when I am back home.

rubydist,

I am embarassed to say that I don't know what the "clutch coil" looks like.

Thanks everyone for the suggestions.

 

[deercrusher]

the clutch won't engage if the coolant pressure in the line is too low. Did you try using one of those refill cans from the parts store - they have a pressure gauge on some of them. Refill to proper pressure then your clutch may engage.

 

[hawkeye18]

the clutch won't engage if the coolant pressure in the line is too low. Did you try using one of those refill cans from the parts store - they have a pressure gauge on some of them. Refill to proper pressure then your clutch may engage.

That's what shorting the plug on the "propane tank" (that's the accumulator/dryer, btw, you can just call it the dryer) does for you. That switch that it plugs into is the low pressure clutch cutoff switch - bypassing it allows the clutch to come on at any pressure.

Well, the high pressure switch will still cut the clutch off, but you have way worse problems if that's tripping.

 

[deercrusher]

Ahhhh haaaa, thanks for the info hawkeye.

 

[projectSHO89]

HPCO was installed only on R134a systems. The 92 was R12 so it does not have one.

Check the coil's resistance as already instructed.

Measure the gap between the clutch and the pulley.

Report your readings.

 

[Sholovenothate]

I figured I wouldn't start a new thread since I have an AC question also. I have a 1990 with stock AC. My compressor DOES engage and spins when I put it on max AC but its still hot/normal outside temp air coming out of the vents... i pushed in one of the little ports and gas will shoot out so i know it has pressure in the lines. I went ahead and replaced the EATC with a hard button unit today and still the same thing.

The compressor is coming on with clutch engaged but not cold air. I wanted to check the coolant level but i can't find the right size adapter to fit. I have a few of those 134a refill cans from autozone and I even bought a Retrofit kit that came with 4 different size connectors for R12 but nothing fits so i cant check the pressure in the lines.

Ideas on what to check/replace ?