1998 Volvo S70 non Turbo

I have looked at a lot of forums on this one and have tired almost everything.

The compressor does not want to engage, I've filled the right amount of freon and replaced the relay. There is power going to the low a/c pressure sensor/switch. The only way I have got the compressor to engage is by paper clipping the relay to jump start the compressor and thats the only way it works. I dont know what else could be the problem?

Any ideas?

Thanks in advance!

 

There is 2 other things it can be. 1. The high pressure switch. 2 The blower motor resistor.
The compressor is tied to both of those items.

 

Thanks for a quick response.

I did check to see if power was coming to both switches. One thats located near the firewall the other thats between the passenger head light and the a/c low pressure port. Both had power going to them. How can I check to see if one or both of them are defective? [I detected power getting there but how about if they are actually working?]

where can I find the blower motor resistor?

 

I do not have the info infront of me do give it to you right now.

The blower motor resistor is under the dash on the passenger side.

 

at the risk of looking like an idiot my question is how do you hook up gauges to check freon ? very little experience with volvos and am guessing this 99 isn't set up for 134 because my ends wont attach to car. is there an adapter ? or am i missing something simple ?

 

The S70's only have a low side port. It is located in the pipes behind the passenger headlight heading to the firewall.