The PBCU on that model doesn't suffer from bad solder joints, I don't believe, it's all electronic (no high-current relays on board).
I checked the PCB on my mom's TE while I was doing the evaporator -- all standard IC type connections, none of which looked bad. I do now have a non-running AC compressor I need to diagnose, any hints of how to determine if it's the PBCU or the KLIMA relay? Peter -----Original Message----- >From: Jim Cathey <[EMAIL PROTECTED]> >Sent: Oct 17, 2006 1:31 AM >To: Mercedes Discussion List <mercedes@okiebenz.com> >Subject: Re: [MBZ] Heat & AC failure > >> The heat and AC both began to fail intermittently about a year >> ago. Sometimes they would work and sometimes not. > >Many of these intermittent failures could be bad solder joints >inside the pushbutton unit. However, could your symptoms be >explained away by a coolant flow valve (known as the monovalve) >becoming incontinent? If 'AC fail' is because it starts blowing >heat, and 'heat fail' is because it doesn't, both can be blamed >on this one valve losing the ability to be properly controlled. >In that case it's an easy and relatively inexpensive DIY repair, >assuming that this _is_ a late 126 car we're talking about. > >Bad solder joints inside the PB array is less of a DIY repair, >largely because in these there are so many contacts inside. >(I've worked on two of them [or was it three?] for other people. >Ugh.) Replacements are so expensive, however, that if you are >a _good_ solderer it may be worth a shot. If you have to go >out and buy an iron first, don't even think about it! > >I have a day job again, so I'm out of that biz. > >-- Jim > > >_______________________________________ >http://www.okiebenz.com >For new parts see official list sponsor: http://www.buymbparts.com/ >For used parts email [EMAIL PROTECTED] > >To Unsubscribe or change delivery options go to: >http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
