1991 740 AC issues

TommyB · Post by **TommyB** » 01 Aug 2006, 11:02

Need help finding the problem with the AC on a 91 740 (No Turbo) sedan. I suspect that the AC relay is the problem, but I can't find the relay itself. The AC works great when it is working. But more times than not it won't come on and there is no voltage at the compressor and the fuses are good. On the 91 740 the AC relay is not in the relay tray located behind the fuses that are behind the ash tray. I was told that the AC fan relay on the right fender in the engin compartment also controled the compressor, wrong! I was also told that the AC compressor delay/start relay was behind the glove box. If this is the case I don't see it. I removed the covers and glove box and have searched both sides of the dash without any luck. Can anyone be more specific on the AC delay/start relay location for a 91 740? or Do you have any other ideas?? Help!!

Post by **billofdurham** » 01 Aug 2006, 11:48

There are two AC relays behind the facia panel. If you can not see them from underneath it may be necessary to do a little bit of dismantling. I would start by removing the instrument panel as this should be the easiest part to get out. 2 screws at the bottom corners, possibly concealed by plastic covers, ease it forward and disconnect the multiplugs.

Hopefully, you will then find the relays.

Bill.

wojeepster · Post by **wojeepster** » 01 Aug 2006, 15:58

I bought the wiring diagram for my 240 volvo 88 from volvo technical publications. it was not cheap ($27) but it shows where every one of the relays are located where evey one of the grounds are and every circuit power on and power off (if needed) It is the best wiring diagram booklet that I have ever seen. With this and terry martin's "How to fix and repair automobile electrical systems" I feel I can fix anything on my car.