A/C problem on '95 850

When engine is first switched on, the A/C works fine. In warm weather,
the A/C continues fine for 10 to 30 min, then cuts out, producing only
uncooled air. At that point, I turn off the A/C switch for 5-6 min, turn
it on again, and cool air resumes for another 5-20 minutes. This pattern
can continue for duration of the journey. My volvo mechanic has never
seen this problem and said it could be various switches, relays, etc.
Before we start this potentially expensive guessing game, does anyone
have any similar experience or suggestions?

 

There is a single wire which goes to the clutch on your A/C Compressor, on
the lower front of your engine. The wire is connected to the clutch via a
temperature sensor which is strapped to the compressor. These often fail,
and Volvo omitted them completely on later models.
It is safe to link-out this sensor, as the high pressure sensor will cut out
the compressor when required anyway.
This is an easy fix, and will cost pence/cents !!
There is also an inline fuse on some cars, near to the temp sensor on the
back of the compressor. The fuse is in a crappy plastic in-line holder, and
normally held in a clip on the rear of the compressor. Check the fuse isn't
corroded. Your problem sounds exactly like the temperature sensor is
knackered though, so remove that from the circuit first.
It worked on my '97 V70, and I'm sure it will work on your 'ol beast.
Cheers.
Joe.
Peterborough
UK.
2000 V70 2.5D (old type engine).
Formerly 1997 V70 2.5D (upon which I came to trust this incredible engine by
completing almost 250,000 miles!

 

And on my 94 850, it was the switch in the cabin. Same thing.
Sometimes it wouldn't work after only a few seconds.Took the switch
apart ( and lost some parts) cleaned the contact ( there were two
before I opened it!) and the A/C works fine...I don't have
recirculation now, but a new switch would fix that.

Ron/Champ 6

1963 8E5 Champ (Champ 6)
1962 Lark Daytona Convertible (Boomerang)
1995 VW Passat (Vanilla..yuk)
1994 Volvo 850 (Tilley)
1973 Volvo 1800 ES (An Clar)

 

Ours does that to...kinda.

Only on very hot days and long drives it will cut out for no reason, then
come back with no reason, and several Volvo techs have not figured it
out--ours is a 97 850 no turbo.

It starts after about an hour then will continue every few minutes
thereafter.

 

Check that dash switch! I'm guessing that sometimes the points inside
the switch are barely making contact, and with the heat of resistance,
they open up...when the switch cools, the A/C come on.


Try this: Pop the switch out, and temporarily bypass it with a generic
switch and see what happens. If all works well, go buy a new switch.

Ron/Champ 6

1963 8E5 Champ (Champ 6)
1962 Lark Daytona Convertible (Boomerang)
1995 VW Passat (Vanilla..yuk)
1994 Volvo 850 (Tilley)
1973 Volvo 1800 ES (An Clar)

 

I noticed in my repair logs that my 95 had the evap replaced in 97 under
warranty, is this just a replacement or did they revise the design?