1998 S70 Air Conditioning compressor clutch not engagin

dcc · Post by **dcc** » 09 Jul 2014, 10:40

I have a 1998 S70 non-turbo and am currently trouble shooting the AC Comp Clutch.
1.) If i manually slug the AC relay the clutch engages and the pressure is good
2.) Jumpered the Low Press. Sw and had no effect
I read about something at the compressor that could be by-passed for testing purposes, but not sure what or where it is. If some one on the site could point me in the right direction I would be most appreciative. I have included a picture of the only wiring I can see coming off the clutch would like to find out what it is.

Post by **cn90** » 09 Jul 2014, 18:04

Search forum for the zip tie trick for the AC Clutch.

Caberguy · Post by **Caberguy** » 09 Jul 2014, 18:27

I haven't heard of the "zip tie" trick, but I've heard of the "bread clip" trick. That might turn up more results...

Post by **dosbricks** » 09 Jul 2014, 18:34

Just dealt with this myself. Here you go. Pics on page 2. S70 clutch is the one shown in the first and last set of photos. If the existing gap is over .5mm this is probably the problem. .3mm is what you want.

https://www.matthewsvolvosite.com/forums ... =1&t=63960

Post by **rspi** » 09 Jul 2014, 19:06

Post by **dosbricks** » 09 Jul 2014, 19:31

Be advised that around 6.08 min into the video Robert says the clutch gap should be between 3 and 5mm which is incorrect. 3mm is about 1/8" and 5mm is close to 3/16".

Usually Robert is right-on with his videos, but the demo of using a junkyard compressor to show him prying off the clutch with screwdriver wedges and hammering the clutch outer assembly back on made me cringe. There is a pressure seal around the clutch shaft and due to its vulnerability in these old compressors, I would only use a puller to remove the outer assembly if you elect to go with the officially sanctioned fix. Just saying.

Post by **rspi** » 09 Jul 2014, 21:26

Thanks for the clarification. The proper gap should be 0.3mm to 0.5mm. When I was at the junk yard I actually called a Volvo mechanic and asked about the gap and that is what he told me. LOL. I just had to regap my compressor again yesterday after 3 years of the zip tie shims being in there. I did make another video showing me doing the zip ties and will upload it soon with the corrected gap information. I used a spark plug filler gauge to measure the gap.

Yes I did hack away at that compressor and do NOT advise doing the job that way. Yes get a puller. I need to introduce myself to a puller and reproduce that video. :p

Post by **rspi** » 09 Jul 2014, 21:41

I made a few notes on the video, they call them bubbles. Anyway, what does a puller look like, one that would be used to pull the clutch off the compressor?

dcc · Post by **dcc** » 10 Jul 2014, 09:09

Thanks for the tip, my compressor does need shiming so I will do that this evening. However does any one have a schematic of that portion of the electrical. I have jumpered out the Low pressure switch,
The High pressure switch with no luck. I have read that the compressor relay gets a ground from the ECU to energize it, but it goes through several sensors to get to the relay. I have 12vdc every where I should on the relay, but am definitely missing the common for it. Any advice and direstion would be most helpful. Thanks

Post by **regent** » 10 Jul 2014, 09:23

Look here for the electrical: http://www.volvowiringdiagrams.com/?dir ... 20Diagrams