AC problem and what system?

AviatorD · Post by **AviatorD** » 25 Jun 2010, 09:53

Hey all,

I have a 96 850GLT. I'm trying to diagnose and fix my volvo's ac system. I have a haynes book on heating and AC systems.
My compressor doesn't turn on from the ac unit inside my car, but when I open my hood, I can bypass the switch with a paper clip to turn on the compressor. So I think I've eliminated that my compressor is broken. Next I bought a recharge bottle, and emptied most of it into the low pressure hose, but my AC will still not work. So now I'm out of options trying to troubleshoot the problem.

Any suggestions as to what I should do next trying to figure this out?

Also another question. Does anybody know what type of AC system I would have (Thermostatic switch system, Accumulator System, Suction throttling valve system, Valves in receiver system, Evaporator pressure regulator) or is there another type that I'm missing?
It's a volvo 1996 850GLT 2.4L engine

Thanks

Retired MVS Contributor · Post by **Retired MVS Contributor** » 25 Jun 2010, 12:41

From the nomenclature cited I can tell you know a little bit about A/C...The 1996 850 has an accumulator and does not have an expansion valve, it has an orifice tube...I suspect that the problem is still a low charge...If the system was emoty when you added refrigerant, then 1 can is not enough...

FCPGroton, pinned at he top of the Matthew's page has all the parts and if you go there and punch in your car's info, it can tell you what you have...

Post by **JRL** » 25 Jun 2010, 13:18

These take almost exactly TWO cans from dead empty. (OK 26 oz but who's counting)
Two oz's low will not make a difference.
If after your 2nd can is added you're still are not working, look to the pressure switch

AviatorD · Post by **AviatorD** » 27 Jun 2010, 17:26

K thanks all. I'll see by adding more freon will fix the problem. When adding the freon, should I have the compressor running? The compressor will only turn on by bypassing the switch. Also, I'm trying to find the high pressure discharge port to measure the psi. I just bought a manifold gauge, so I was thinking of doing a static diagnostic check. Do you know what I can find the HP discharge port?

Post by **Pauloil** » 27 Jun 2010, 20:22

yes compressor running when adding freon
what I did today was attach my simple hose with valve open to the can so I wouldn't open it yet and then attached to the low pressure port with quick connect. a-c on high, windows open. pierce the can then open valve. the can gets cold as the freon goes in over 5-10 min. at the end turn can upside down until empty

AviatorD · Post by **AviatorD** » 28 Jun 2010, 15:52

Hey all,

I just added the Freon, about 24oz. I had to jump the switch to turn on the compressor. As I had the ac on, I could feel the cold air in the cabin in the car when I sat in there, to see if the ac was running through the system. When I was done with adding the freon, I plugged the ac switch back into this plug looking thing that was connected to I believe the low pressure tube. Now I have another problem. When I turn on the ac, the compressor won't turn on. I don't know where to go from there. How can I make the compressor turn on from the car like it's suppose to? Thanks all again

Post by **Ozark Lee** » 28 Jun 2010, 16:02

If it ran with the low pressure switch bypassed and it won't run when it is plugged back into the switch it suggests that the switch itself is bad. The switch is relatively cheap and easy to change.

...Lee

AviatorD · Post by **AviatorD** » 28 Jun 2010, 16:30

Where would I get the switch? and also how would I change it? Thanks a lot

AviatorD · Post by **AviatorD** » 28 Jun 2010, 16:35

Would it be this switch Volvo 850 A/C Pressostat? Thanks again.

Post by **Pauloil** » 28 Jun 2010, 16:40

is one of these your switch?

http://www.fcpgroton.com/category-exec/ ... by_year/46