PeachParts Mercedes-Benz Forum - View Single Post

bustedbenz · #1 08-07-2009, 01:08 PM

In chasing my climate control problems (A/C is cold when it works, but cuts out fairly early in a trip and can never be persuaded to re-engage) I've decided to try a different dashboard "computer" -- replace the control box and see if it's sending bad signals to the system. Doesn't cost me anything to try, IF I can use the parts I've got.

I went to pull-a-part two or three weeks ago and got a climate control unit that looks like it's in MUCH better shape than mine. The buttons press more firmly, it wasn't covered in dust, the temperature wheel has a firmer rotation and clicks into the detents more strongly; it appears to just be generally less worn out and possibly okay. There's a tag on it that says it was inspected and found okay in 2001, which means it was somebody's rebuild/replacement. Point is, I'm optimistic enough to assume it works at least as well as mine does until I learn otherwise.

Here's the catch. It's out of a gasser w126, not sure which one or what year but I think it was late 80s. I know for a fact that it's the same "generation" of w126 as mine, rather than the older one. I haven't checked each plug to see if they match but IIRC from last time I had mine out a year ago, they seem to. It has the exact same complement of rocker switches up at the top for defrost, hazards, etc; in the same order with the same markings, so I'm assuming they're identical switches if the pins all line up. (I just took the thing out with the whole wood trim piece and all the switches, since the wood looks better than mine too. Going to change it in as a unit.)

Is there any reason that shouldn't work? The only visual difference I see between my button box and the potential gasser replacement is that mine has a very thin "O" marking on the off button, whereas this one seems to have been printed in "bold". Everything else seems identical as near as I can make out. Does somebody know that they in fact do completely different things under the dash or run on a different voltage or something? If I were an engineer, I'd put the same climate mechanisms in any w126 no matter how it was powered, but I can't assume that without somebody saying "Sure, try it, you won't shred anything."