weirdest AC problem

turbotim2 · Post by **turbotim2** » 13 Jun 2005, 11:32

You should be getting about 35-40 psi on the low pressure side of the AC system. It sounds like you don't have enough in it. I would doubt the compressor is bad if it is making cold air at times. I would check the switch if adding more 134a doesn't fix it.

JAZ · Post by **JAZ** » 13 Jun 2005, 13:03

Extacly what does the switch control ? is it located right beside the low pressure valve.

turbotim2 · Post by **turbotim2** » 14 Jun 2005, 07:46

The switch is a pressure switch that will shut the power to the compressor off if the pressure is too low. The switch maybe next to the line port... I can'r remember off the top of my head. Other cars have them right on top of the canister or very close to it.

JAZ · Post by **JAZ** » 14 Jun 2005, 08:56

Do you know if it is possible that the compressor acutally doesn't pull enough voltage and stops and restarts. Seems kind of weird that it would do that. I would figure that it wouldn't work at all. never seen anthing mechanical stop and restart on voltage issues.

JAZ · Post by **JAZ** » 14 Jun 2005, 11:11

Trying to find a used switch and several come up. Is the real name for the switch. is the real name Pressostat switch or is it the Map sensor that i have to change?

turbotim2 · Post by **turbotim2** » 14 Jun 2005, 12:09

I have a friend here who's Dodge is doing the same thing as you described. I checked it out and it seems the pressure in the system is good but there must be a conflict between the low pressure switch and high pressure switch. It kicks the compressor on for about 2-3 seconds and then it stops without making cool air. I tend to think this is caused by a faulty high pressure switch. I will do some more research on the Volvo.

JAZ · Post by **JAZ** » 14 Jun 2005, 12:48

Well it seems that maybe that duracool stuff i was bragging about isn't so good after all. It might cause pressure problems thus making the AC switches shutoff the system. Might try to pick up a used cut off switch and give a try but sounds like a complete flush and refill of 134a.

regardless · Post by **regardless** » 15 Jun 2005, 10:10

There might be a chance the the Linear Map sensor is worn Volvo part number 8628563. If a 134A charge increased the cycle time for the compressor and the ac quit after rpm above 3000 the map sensor is a good canidate for inspection. Located on the high side AC line Pass side just behide the rad core support. It has a 3 wire connector and sends a resistance value to the ECC for the high pressure circuit of the AC system. When they become worn the resistance increases. That signal gives the ECC an incorrect high pressure and opens the compressor clutch circuit.

JAZ · Post by **JAZ** » 15 Jun 2005, 11:16

Well, decided to take it in for a flush and a fresh 134a refill. Guess what? Flush worked great but the mechanic wasn't able to refill it. It just wouldn't take in the gas. He thinks that maybe there was too much duracool in it and the evaporator might a froze while i was driving down. Going to wait a few days to let it warm out and going to try to refill it.

JJBreaks · Post by **JJBreaks** » 13 May 2012, 20:56

The ac compressor has the switch internal, when the switch overheats it cuts out the compressor. Replace the compressor, it will fix this.