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sprinkles08, ASE Certified Technician
Category: Car
Satisfied Customers: 22813
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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Oldsmobile silhouette: 2002 Olds Silhouette Premier A/C quit

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2002 Olds Silhouette Premier A/C quit working. The van has 3.4l sohc, front and rear a/c. dvd player. The A/C has been working great then it just quit, compressore clutch is not pulling in. I check the fuse and relay under the hood box, both are good. I put my scanner on it(snapon mt2500) When I did the test to request a/c with the engine off, key on, the compressor clutch pulls in but its backwards to what the scanner says, i turn it onwith the scanner, i hear it click, the scanner says its off, when i turn it off, i hear it click and the scanner says its on. When i start the engine, it wont click at all, The scanner says the freon has to be charged to get this test to work so i think it has enough freon, what to try next?

Hello and welcome to JustAnswer!


With the actuator test you verified that the relay, clutch coil, fuse, PCM and wiring are all good.


The problem could be a handful of things.


It could be the control head not sending a signal to the PCM to turn the compressor on, but that wouldn't be very likely.


It could be low charge. The actuator test will run regardless of whether the system is charged or not. The most common cause of an a/c compressor not engaging is low charge.


It could be the a/c pressure sensor. The pressure sensor monitors actual pressure in the high side of the system and the compressor will be disabled if pressure is too high or low. To check the pressure sensor you can compare it's reading on the scan tool against what you see on the high side manifold gauge. If it's not showing the correct pressure then it could be wiring but is most likely the sensor.


There is also a temperature sensor on the evaporator that could be bad and preventing the compressor from engaging but failures of this sensor aren't that common either.

Customer: replied 4 years ago.

My scan tool doesn't show anything for the a/c except the a/c request, and when i request it, turn it on, the scanner says its turning it on and shows its off and when i turn it off, it shows its on and i can hear the clutch pull in? So should i just go down your list of could be's?

Yes. The first thing you want to do is make sure the system is fully charged and go from there.
sprinkles08 and 7 other Car Specialists are ready to help you
Customer: replied 3 years ago.

it was empty on freon, so i put two cans(24oz) its blowing cold, it must have a slow leak as the first worked for 2 weeks when i got the van. What should the pressure be? i have a manifold gauge now.

Can you estimate the temperature in the area right now? Pressures are temperature dependent.

Customer: replied 3 years ago.

91f outside , the gauges showed blue 115psi or 35 on the r134a scale and the red 34psi or 34 on 134a scale


At 86-95 degrees ambient temperature and humidity over 50% it calls for 34-45 PSI on the low side and 187-254 PSI.
Customer: replied 3 years ago.

after 10 min running the low is 32psi and the high is 195 so its close, how much freon does the system holed?

Yes, that's pretty close and maybe slightly low. If you have a front only system then it calls for 1.68 pounds, if it also has rear a/c then it calls for 2.2 pounds.
Customer: replied 3 years ago.

i put 2 12oz in so another half can should do it right. thanks and are the pressure ratings for any a/c system?

If you have front and rear a/c then another half a can should do it.

The pressures are fairly universal but these are the exactly ones specified for your van.
Customer: replied 3 years ago.

yes it has rear a/c so i'll add the half can, it leaked down is why it quit working so next time i'll add a can with dye to find the leak, should i add oil or does that stay in the system with a slow leak? thanks for you help.

You'll lose a bit of oil with a leak. I'd add an ounce or so each time it's charged to ensure the compressor isn't damaged.
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Customer: replied 3 years ago.

what type of oil? pag100?

They specify GM part number 12345923 but it is the same as PAG 150.
Customer: replied 3 years ago.

thanks, i'm trying to recharge the system again after fixing the leak(hole in line to rear a/c) last time the compressor kicked in while putting the first can of freon in, this time I have put 1 can in and have the second can hooked up but the compressor hasn't pulled in yet, is there a pressure switch i can jump to get the compressor to pull in?

It uses a pressure sensor rather than a switch so you woudln't be able to jump it that way. You can either apply power directly to the compressor or you could jump the relay. If you jump relay pins 30 and 87 it should turn the clutch on.

Customer: replied 3 years ago.

my bad, the compressor is working, i just couldnt tell so i had my wife turn it off and on to make sure. thanks again

You're welcome!