i was told that the A/C on this 1993 850 my friend is looking at only works when it is in gear (standard). i can't find a reference in the owner's manual. is this true?

It sounds to me as if there are a bunch of 850/70s with electric fans that don't work for whatever reason(s). The fan is controlled by pressure switches in the freon system. If the fan doesn't run, the compressor will run only long enough to build high head pressure(because of a lack of heat transfer), then the high pressure switch will turn it off. There is a flat wiring harness connector with four wires in it, two black, two brown, directly beneath the right hood latch, that carry the pressure switch wires. Make sure they are all connected. I had to push one farther into the molded connector on my '95 850GLT with manual tranny. Before I found that, I had very similar symptoms to what I have read here.

It should disengage the compressor at certain points, usually depending on the needs of the engine. Under heavy acceleration and when at slow speeds, mine does that, BUT make sure you have a full charge of freon. If you are running low, it will make a difference...

Mine did until I got it charged.

Shawn

wxrman,
Thanks for agreeing with my earlier thread. If folks check there owners manual they will find that the A/C does indeed disengage at low and high speeds. This is not to be confused with the A/C shutting off. Cold air will still blow, the compressor will just disengage for the moment which makes a lot of sense, especially under full throttle.

If You don´t have the fan set at 0 the A/C should work independent of
gear/speed.

I have a manual S70 and the A/C works in any gear including neutral and also independent of the clutch, wipers, windows, radio station or my wife's moods.

Good luck.
--
Vladimir. 1998 S70. Base, 5-speed manual.

vladimir,
I am curious as to not owning a manual....are you saying that your compressor engages when in neutral or at low speeds unlike the automatic? What I posted is definately true for automatics and I can't see why Volvo would make the manual any different. Remember, we are talking about the compressor only engaging and disengaging. Even at low speeds and high accleleration, my car will still blow cold air, but don't expect the compressor to engage.

Yesterday merging back onto the Palasides Parkway from a gas station I had the AC on. Got scared to death too!!! The ac kicked in and killed my acceleration as I was trying to merge into too fast rush hour traffic. My guess is it doesn't cut off or disengage on the sticks. I don't know why either since I have noticed it to be a safety concern both merging and slow speed/rpm city. *sigh* if only I had a turbo...

-J

'94 855 200,000 miles later today!!!

sablefish,
Sounds correct, check the manual for sure. On automatic transmissions the air conditioning disengages at speeds under 20mph/40kmh. Likewise, it also disengages when under full throttle (which is kinda smart). This is all true for my '94 850.

I think this is False. The AC has nothing to do with the Transmission or the Clutch.

If it only comes on in Gear I would call a Volvo Shop and talk to a Service Tech and they will probably say the same thing.

Sounds like someone has played with the wiring.

You should be able to start the car put on the E brake, put in in neutral, and turn on the AC with no problem.

IF this is true you would have to charge the system while driving down the road and that would be pretty tricky.