1998 volvo s70 air conditioner not working.

Car: Volvo, S70, 1998 - Back to Fix-It - Volvo Repair Manuals

Q.1998 volvo s70 air conditioner not working. fans come on for condenser when button is pushed for ac and when I jumped out the low pressure switch. My question is about the ac relay in the main fuse box.
Checked out coil and it is good. When I jumped the no contacts for relay the compressor starts and I have cold air with a low pressure of about 30 psi. I have read about shimming the clutch but it sounds to me that if the clutch needed to be shimmed it would have not picked up. What does control this relay?

Answer There are 3 relays in the system, and My wiring diagram at home does not distinguish locations, just functions. My initial impression, was your pressostat was showing bad pressure.
This is a 3 wire pressure sensor, and its more sophisticated than the low pressure switch. Based upon pressure interpreted, the ECM makes a decision (via a relay) to cycle the compressor off. We call this signal A/C approved Yes/No. I feel fairly confident, because I have seen many 98 s/v 70's with this sensor failure. This sensor is located behind the passenger side head light. If you look down, towards the charge port you will see it.

Addition is there a way to jump or overide this switch to test it or a way to bench test it?

Answer Test this sensor, by monitoring it through our scan tool. When the a/c comes on you should see pressure changes from the ECM. This is how we are certain of that components failure. Not sure if a generic scanner will pick this up or not. YOu could try though.. most autozones will scan your car for freeee..

Addition Will the scan tool will pick up that sensor if it has failed or does it give the actual pressure reading? If this is the case than I'm assuming that since it is a sensor and is monitoring pressure that it is not just a open and close type of switch which again there is no way to jump it out? I did notice one thing though, that when I tried to run the ac while I was driving the abs and trac lights came one. This only happened when I tried to see if the ac would come at several different times of attempts of curriosity. When I shut the car off and turned it back on the lights will off. Is there any connection between the two? The ac never came on though. How expensive is this sensor and can I change it myself?

Answer I do not have access to the parts pricing for this sensor, so I can not give you an Acurate price. If you want a price I will have to get it tomorrow since I am on the east coast, and my suppliers are closed.
As to the scan tool, will it pick up the sensors values? That is really up to the scan tools manufacturer. It will not point out and say the a/c pressostat is bad, it just does not think that you have the a/c on so it never approves the a/c to go on.
As to, can you replace this switch yourself, you can. There is a schraeder valve in the line. So its a matter of unscrew old, and install new.
Your impression of this sensor was correct. Its a variable resistor of sorts, It senses pressure and its value changes as a result. It is not a simple open/close switch.

Addition Few more question I hope. Is the low pressure switch wired in series with the clutch?
Is there a way that I can obtain the wiring diagram for the ac circuit?

More Info required do you have electronic climate control? Or manual climate control..
Electronic climate control has numbers on the setting dials (ie 50,60,70 degrees)

Addition manual with red and blue around the dials.

Answer If you send me an email at my address.. I will send you the page out of my personal digital wiring collections. I do NOT have a complete breakdown of what each number means (ie, what 5/23 is) I would hope you consider this way above the original answer.

Addition The three wire pressure sensor that you discussed earlier I assume is on the high pressure side.
when I disconnected the plug the condensor fans shut off and when I connected it back on the fans started back up again. Looking at the print the ground for my ac relay comes from the ecm. I have 12 volts on the other side. Could my ecm be bad because I was told that sometimes the ground wiring for the ac control relay burns up and opens? I was also told that during acceleration that this unit will shut the ac off until done accelerating for max power. If taken to a volvo dealer, with their scan tool, could they determine if that was the case?

>>Contribute your Answer<< - Submit your Question

Home Info JDM Chat Free Car For Sale Albums Members Video Bumper Stickers Dealers

Advertisement [ ? ]

Site Links

1998 volvo s70 air conditioner not working.