98 Volvo S70 GLT A/C Compressor fault. Replaced AC switch 30767231, 8628563 Topic is solved

[robl245]

Same here on my S70. Please post your results. Just had mine at the shop and he was able to bypass the relay to get it to turn on, and verified the high and low pressure switch. He just returned the car to me and said it was probably the computer. The car runs and I drive it to work everyday. Or I did until the temps outside started getting close to 100 degrees since the AC doesn't work. I'd really like to get the AC working.

[timmykelly]

My 98 S70 has the exact same symptoms that robl245 describes. My mechanic can also get compressor to run by bypassing the relay. He confirmed the high and low pressure switches work. Additional testing lead him to believe there is a short somewhere. In his words, he believes "the quad driver in the computer is supplying power when it should be applying ground." I too drive the car to work everyday, but it's tough without AC up here in Boston.

[timmykelly]

Update: I forgot to mention that I swapped the relay out with a new one, and the AC compressor still did not run. I also swapped out the ECC from above the radio with one from the salvage yard, and that did not fix the problem either (although I don't know if that salvaged ECC had problems.)

[abscate]

It's wiring. One of your required inputs to the ECU is not making it ...or the output from the ECU isn't reaching the ground on the relay.

Wiring faults aren't glamorous to find, but if you are systematic they can be slain.

[timmykelly]

Thanks for the advice, abscate. I'll do a visual inspection to see if I can find any cracks, etc. I'll mention this, too, in case you think it might be related: When I pulled the radio out from the dashboard, I noticed that the solid red wire extending from the back of the Electronic Climate Control had been pinched by the radio when it was last inserted into the dashboard. There aren't any cracks in the insulation of that red wire, but there is an indent in the insulation. Not sure if this might have anything to do with the compressor not running, but wanted to mention it because it's connected to the ECC.

[timmykelly]

I had my S70 at the dealer today. They determined that an error code indicated that the "line pressure switch" was not functioning correctly. They replaced it and the compressor is now functioning. The switch they replaced is what davidmk31 shows in the photo posted on the previous page of this post. Very frustrating to pay the dealer to replace this, especially when you consider how easy it is to access and remove. I could have done it in 10 minutes if only I knew this was was the problem. Ugh! Hopefully others can benefit from this!

[pb49415]

Which two terminals on the high pressure switch did you test for continuity? My switch is definitely broken, (completely severed from harness) but I want to jump across the connection harness to see if my compressor will engage.

[abscate]

Added part numbers to title for search on AC high pressure side switch

This is a 1998 1999 2000 MY part. Terminal 1 is ground through ECU, measure voltage on harness on terminals 2 and 3 with harness disconnected. One of them will be 5 V, the other will be the one to check resistance in the switch between that pin and pin 1

Resistance soecs per chart

Ac high pressure switch specs

[vlr7]

Does anybody have corresponding resistance values measured of a working sensor. Im getting 20kohm. fol-fcr is showing pressure somwhere 2400kPa which is obviously too much. Engine TDC is showing code EFI-225 Air conditioning pressure sensor signal.

As a remark, i have three non working sensors, two of them show 20kohm, one shows 40kohm.

[abscate]

I can measure on my 99 if you tell me which pins you want measured