when I turn on the a/c nothing happens. I have repaired some lines and then put 1.6 pounds into the system. it holds presure and when i jump the compressor clutch wire it kicks on and the presure drops and it gets cold like it should. I read other threads and jumped the connector on the low side near the firewall, nothing happened. I then saw a switch near the low port and pulled it off I jumped some of the wires and the compressor kicked on but only for a second then turned back off.

any help or direction would be much appreciated. thanks

 

There should be a relay in the relay box under the hood.
The reason the compressor came on from the one switch is because you jumped the high pressure switch but since there is 3 prongs in the switch it also needs to see the cooling fan on which is the other prong on the switch.

Try grounding the connection at the low pressure switch by the firewall.

If it comes on then it is either a relay or the connections at the relay.

 

well I tested the relay and it works. when i plug the switch at the high side the clutch kicks in and the fan comes on but the clutch stays on for about a second junping the switch does nothing and the relay works fine. does the relay have a circut protection on it.

any other ideas because im stumped

 

Did you try checking the ground at the low pressure switch like I said to?

The S70 system works with the low pressure switch grounding the system.

The 850 works the opposite.

 

Tech,

Please help, I have similar problem with AC. The AC worked last summer, although it leaked slowly.I had toadd one can of R-134 in two weeks or so. This summer, the compressor would not kick in at all. I could make make the compressor kick in byshortcutting low pressure sensor plug. I wanted to force the compressor to suckR-134 this way, but it did not work. Is the compressor shot? Where would you recommend to start to fix AC? I am committed to fix it substantially this time. Thank you!

 

...forgot: mine is 1998 S70 T5

 

the ground is good and nothing happens if I manualy ground the plug. if I unhook and plug back in the high side it will run but only fo a few seconds. I think it might be something with this plug or on the high side. the relay is ok, but if it has a circuit protector in the relay then the clutch could be drawing to much energy or something. I am stuck and I realy dont want to just start throwing parts at it so any info would be great. thanks

 

If you jumped the low pressure switch and it will run then it must still be to low or the low pressure switch is bad.

 

Are you 100% sure the relay is good?
Try jumping the relay connection and see if the compressor comes on.

 

this is only geting better. now I have no power to the relay. where does it come from? I jumped the relay and I am sure that it works. I had power before and now I dont, this is so screwy! when i jumped the relay the same thing happened when removed and then pluged the high side back in rapidly, the comp would come on for about a second. if I did it fast enough it would stay on, but now that i dont have power I cant even do that. my check engine light is on but I think that is from removing the fuse to the A/C

help

 

If the check engine light is on there might be a code stopping it from coming on.

I will have to try to get a copy of a wiring diagram and check it out.

 

sorry the power comes from the climate conrtol and the diagnostic conection it was blown. the same problem is with the high side switch so not new info other than the fuse. the presure on the low side drops to 30-37 so I think it is all working well I just cant figure out why the high side would be causing problems.

 

Maybe the high pressure switch is bad.

I would really need to see the car to help much more.

I will still try to get the wiring diagram for you though.
Been buys at work and Boss hanging around alot.

 

What year is it?
If it is a 1998 I have a diagram.
The 99 and up is to light in the computer program to get it printed out.

 

it is a 98 and i am wondering if there is something wrong somewhere else. becaue it does the same thing when I jump it with the wire. I dont know what to do now In lost.

 

I can get you a 1998 diagram it might be easier to e-mail you with it.
If you want it PM me with your e-mail address.

 

is the safety and the high switch in the same place? if not where is it?

 

The high pressure should also be the safety.

 

is there any other relay that could be messing up? someone mentioned a relay behind the glove box.

 

The one behind the glovebox is for the Fan speed. Some say it will stop the compressor from working but I have never seen that.