1992 940 Air conditioning

gameboo · Post by **gameboo** » 23 May 2007, 21:44

I have a 92 Volvo 940 turbo. 120,000 miles. The air conditioner does not work at all.

I hit the air conditioner on button and do not hear any clicking noise under the hood. Does this mean that it is the compressor? or could it be a relay? or something else? I dont know much about air conditioners. I know there is an evaporator also, but dont know what that does.

Is there an easy way to diagnose the problem?

Also, does anyone know where the relay or fuses are to check air conditioner? what number fuse?

Thanks,

Post by **billofdurham** » 24 May 2007, 12:39

The most common cause of failure in the A/C system is lack of refrigerant. Once this gets too low the compressor automatically stops working.

It is possible, in the US, to buy cans of refrigerant and top up the system yourself. There is plenty of guidance in the Air Conditioning section on this site.

It may be that the refrigerant is low and the system will work when it is topped up. However, if there is a leak this will be short lived.

On the 940 the condensor is mounted in front of the radiator and is prone to damage from stones and other debris thrown up by vehicles.

As you admit not knowing much about the A/C, I would suggest you take it to a professional, not a Volvo dealer, and have the system checked for leaks.

As for fuses and relays there are none that would stop the A/C working. The only fuse and relay are to protect the heater blower.

Bill.

gameboo · Post by **gameboo** » 26 May 2007, 02:52

if the compressor was good and the system only needed more refridgerant, wouldnt you here a clicking noise when the air conditioner was turned on?

Post by **billofdurham** » 26 May 2007, 12:40

The compressor is protected by a pressure switch operated by the refrigerant. No pressure, no compressor.

Bill.

gameboo · Post by **gameboo** » 10 Jun 2007, 02:20

I checked the pressure in the system and it was high. So there is something else wrong. Are there any easy ways to figure out hte problem? besides randomly choosing parts to replace?

Thanks,

An AC Noob

ken goodman · Post by **ken goodman** » 10 Jun 2007, 11:17

turn the system on, wait for the delay time to pass, get a test light and go to the cycling switch on the accumulator. there will be two green wires going into the switch check for 12vdc at one side or the other if you have 12 volts present the problem is probably the compressor clutch . {assuming the pressure in the system is actually ok] if there is no voltage present, the problem is in the a/c controller unit. unless you can disassemble the unit to attempt repairs, you are not going to like buying one.

gameboo · Post by **gameboo** » 15 Dec 2007, 15:15

is the compressor clutch difficult to repair with regular tools?

Post by **billofdurham** » 15 Dec 2007, 15:48

This link shows how to re-shim the compressor on the 850. The basic principle is the same.

http://www.volvoforums.com/m_34431/tm.htm

Some manufacturers do specify special tools but I think that, with a little ingenuity, the job can be done without, as shown.

Bill.

gameboo · Post by **gameboo** » 15 Dec 2007, 17:45

1. Is there a way to know that it is the clutch for the compressor and not another problem in teh compressor?

Also,
2. What is the best way to get to the compressor to take it out? Do you have to remove any parts to get to it?

3. The system has to be drained of R134. Without the special air compressor device, what is the best way of doing this?

4. After you remove the compressor and go to put it back in, do you have to fill it with lubricant? or R134 first? Or do you just refill the entire system after putting everything back together at the very end through the refill valve.

5. Do you need to replace the Orings on the compressor?

6. Do you have to replace the Receiver/Drier? if you are pulling out the compreesor.

THanks, and sorry for so many questions.

gameboo · Post by **gameboo** » 25 Dec 2007, 15:50

i fixed it.

I think there was a loose connection between the two green wires and the drier. When i reconnected it, the ac started cyling a bit. I refilled it, and it got better. So it seems ilike its working. We'll have to wait till summer to see.

Thanks all.

Rich