OK, guys, pile on. I'm in unfamiliar territory here, and could really use some direction:
1992 300E 2.6, complaint is AC compressor won't come on. Original complaint was that the #7 fuse was blowing, killing all ACC related functions. Fuse was replaced, and now ACC functions as expected, that is, fan speeds, doors, heat/defrost, etc. Everything works but the AC compressor. I shorted out the low pressure switch with no result. Checked for power in the harness to the low pressure switch in reference to ground and got nothing. This model has a MAS relay which may or may not play a part in this, but I don't have a schematic, so if anyone does, I would really appreciate you forwarding a copy to me, as that would make my life significantly easier in identifying the problem. If I pull the MAS relay while the car is running the engine dies, as I would expect. Since it's supposed to interface with all sorts of things like the fuel pump and other goodies, it appears to be working as intended, as everything else on the car works perfectly. I have to believe there is a failure in getting a signal to the compressor clutch, but without a diagram I'm swinging in the proverbial wind. I would put B+ to the clutch, but I'm unsure of what wire is which, and I don't want to smoke the speed sensor in the process. >From what I can glean, it appears that power comes in, goes through the low >pressure switch, and then on to the compressor clutch. That's an educated >guess based on what I am seeing, but I'm not tearing harnesses apart, either. >There are three wires going to a connector on the top of the compressor, two >of which go off in a separate harness that heads up under the air cleaner. The >remaining wire goes to one side of the low pressure switch. I am assuming the >two that head into the engine harness are for the speed sensor. Dan _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
