I have a 1991 Volvo 240. I had the A/C system converted and charged earlier this summer for about $300. Whenever I run the A/C and am idling, the temperature gage creeps up near the red - it never goes into the red, but I'm worried about finding out what will happen if I do.

When I took it in to have it fixed, the part they needed is the A/C High Pressure Switch. They called Volvo Canada, and found out that this part is no longer in production or carried anywhere. They have tried a few wrecking yards so far with no luck.

Is it possible to bypass this switch without the fan staying on? What are my other options? The car is in mint condition with very low kms, and I have no intentions of selling it soon, so I really want to figure out the A/C problem. I can't believe they don't still stock this part. I've tried googling it to death but I can't find the high pressure switch - just the others (I assume there's more than one type). Maybe it goes by another name?

Also, is it possible that this problem is unrelated to the high pressure switch? Could it be something else that is causing the car to heat up like that? I've had the thermostat and temp sensor replaced already this year, just had the mass air flow sensor done last week.

Does your car have 2 fans or just one?

The high pressure switch doesn't turn the electric fan on.The A/C panel should turn it on.

You should also be able to wire the fan to come on with the key.

seems 2 separate problems

1 if temp on engine is rising too much it is problem with rad or fans or ign timing etc [like if you turn a/c off does temp still rise??]

2 the HP switch [if there] is to protect the compressor IF engine temp gets too high - it can be got from any air con dealer and is generally auto reset - but if your engine temp runs OK you dont need one

I don't work on the car myself, I get it serviced at a Volvo dealership - after I monitored it for a while, it seems that I only have the temp problem with the A/C on. If I'm not running the A/C the temperature remains relatively stable in the car.

If the switch doesn't turn the fan on, what does? Why would the technician think that there was a problem with the switch, in that case?

I'm not sure how many fans are in the car - it's a 1991 240, nothing special (not a DL or whatever) - the reason I can't just use another part is because I was told that this switch was different in the 1991 model year - they tried to put another switch on it from another year, won't fit.

Do you know if you have a switch in the radiator?

If so you can by them still.They are there to come on at a certain temp.

You might have a clogged radiator or a bad thermostat.

yes I think the dealer has confused you

an HP switch is a cutout safety in the discharge of the compressor

as for fans, generally condenser sits in front of rad and the rad temp controls any fans [except like in mine where fan is direct via a "vicious coupling" ie not electric]

so if a/c is on and extra heat from condenser feeds into rad then the rad controls will simply start fans before they normally would

but if all fans flat chat and rad temp rising you simply have a cooling problem [most likely a dirty rad (inside/outside, or both)] but could be engine eg t/stat jammed etc - just hope it is not head gasket!!!