rwj383

I knew it was a matter of time. All the button backlite bulbs are inoperative on my 01 Coupe electronic Dual Zone HVAC controller. I believe it is an internal issue because about two weeks ago a few of the buttons backlites worked while several others were dead. I took the controller out and disassembled it to learn all the bulbs are on a parallel circuit, so if the external power or ground were the culprit then all the lites would have been dead. None of my Alldata schematics go down to component level in any controllers, so I need a starting point with this problem. As well, and likely unrelated, the top two DIC soft keys ( 1-Fuel, 2-Gages) the backlites are out too. Alldata schematics show a common ground and power to all six softkeys, so it seems the mini bulbs dead too????

Any info on these issues would be great.

dgrant3830

The bulbs do burn out over time and all you can do is to replace them. I suggest doing them all at the same time. Since you've already had it apart and now none of them are working, I'm guessing that you used too much heat on one joint that opened the source or ground to all of them. I suggest using a meter to reverse track it to the failure. I don't have the schematic but that's what I would do.