OBC and tachometer lights not functioning when headlights are on

[seandickson]

During normal daytime driving my OBC is easily readable however when I turn on the headlights the backlight goes out. The tachometer backlight is also not working. When this first started occurring it would only happen intermittently and both lights either worked or didn't. Is there some sort of relation between these two lights? I have replaced and tested the tachometer bulb and also checked the contact of the bulb and it all seems good. Has anyone seen anything like this or have any ideas?

[audiquattrot]

had a similar issue, and found out I had fried the instrument cluster circuit board. I opened up the cluster, and saw the burn marks. Yes the back lighting for the OBC & Tach are related. Have u checked the fuse in the fuse box to see if its good?

[seandickson]

Thank you.
I haven't check the fuses yet thinking that was unlikely since it would work and stop randomly, although it hasn't worked correctly in a while. I will definitely check that. Can the instrument cluster circuit board be replaced or do you just have to replace the entire unit?

[audiquattrot]

I just replaced it w a donor one my friend had laying around. I swapped my gauges and bulbs to the replacement one. Was easy to swap.

Here is what mine looked like burnt

http://www.r3vlimited.com/board/showpost.php?p=4139763&postcount=9

Be sure that the right amp fuse is in there. In my case I put a 10amp fuse as opposed to the proper 7.5a fuse....#23 fuse...and there was a short in the system that fried this