That's the classic sign of it detecting belt slip Sent from my iPhone
On Sep 30, 2013, at 6:22 PM, "WILTON" <wilt...@nc.rr.com> wrote: > Compressor "reboots" by turning engine off and restarting. 'Don't know how > long it runs before quitting again - maybe 5 min. or so en route. > > 'Haven't noticed any belt prob; 'check more tomorrow. > > Thanks. > > Wilton > > ----- Original Message ----- From: "Peter Frederick" <psf...@earthlink.net> > To: "Mercedes Discussion List" <mercedes@okiebenz.com> > Sent: Monday, September 30, 2013 3:20 PM > Subject: Re: [MBZ] 124 Climate Control Unit/PBU > > >> Also check the condition of the serpentine belt -- if it's slipping on the >> compressor pulley, it will cause the KLIMA to drop the compressor out until >> you restart. Not the issue if the problem comes and goes, but when you >> notice the compressor not running, cycle the key off/oh and see if the >> compressor starts running again. If it does, it's likely a Klima relay >> related issue, either speed sensor or bad relay (cracked solder connections >> is the usual culprit). >> >> However, it's also possible you have a bad clutch coil or inoperative low >> pressure switch or possibly a bad high engine temp sensor -- easy enough to >> isolate. >> >> Switch ignition on and set climate control for full cold/high fan. Start >> engine and wait a few seconds -- AC should engage around 10 sec or so. If >> it does not, drive it til it quits working, then start checking. >> >> On the pressure switch connection on the receiver/dyer (wires spade onto >> the switch, the ones with pigtails are the fan switch), one wire should >> have 12V, the other not when disconnected. The dead one should be grounded >> via the PBCU. If there is no ground, it's the PBCU, if there is no voltage >> it's the Klima. If you short the wires together and the compressor comes >> on, it's the pressure switch since you have a full charge. Plug the wires >> back into the switch (check for continuity if necessary). >> >> If you have voltage and a ground as specified and still no compressor, pull >> the connector on the compressor and check for 12V on the hot lead -- if >> not, bad relay in the Klima, if it's hot, check the coil resistance on the >> compressor, as an open coil obviously won't work well and one with a short >> will burn the contacts in the Klima relay, causing intermittant or erratic >> operation. >> >> I need to do this on the TE, as the AC croaked a month ago on a trip to St. >> Louis. It was cold enough yesterday and today I didn't need the AC, but >> sooner or later it will be nice not to roast. I have the same issues -- >> adequate charge but on the trip over last time I had to reset the Klima a >> couple times, and then on the way home it quit altogether. Check the charge >> and while it's probably a bit low, it's certainly high enough to run and >> shorting the switch leads doesn't kick the compressor on. I've suspected a >> bad PBCU for a long time (lots of mode switching behind the glove box) and >> everything else is good including a new coil on the compressor a couple >> years ago. Only thing that's possibly flaky other than the PBCU is the >> used Klima I put in after the original burned up due to shorted clutch coil. >> >> Peter >> >> _______________________________________ >> http://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 > > > _______________________________________ > http://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 _______________________________________ http://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
