Driving on the highway suddenly the OBC display went almost invisible, but is still working. Some days later it worked fine again for awhile (letters in orange color), but then it went off again.
Is there a dashlight behind the LED?
Thanks for any help.

 

Hi Frolich,

No need to worry. The OBC is backlit by two bulbs. They are easy to change, but you need to remove the steering wheel to get the rev counter out.

Take care,

 

Jenskleis is right, the bulbs are easy to change. However, I did not have to remove the steering wheel to get the guages out. Just follow this
link for instructions on gauge removal.

 

What type of bulbs are needed for this repair? This is a life saver as the replacement OBC and Gauge (which porsche recommends to rectify the problem) costs £600!

 

I need the answer to this question too! Thanks! Anyone?!?

 

964.641.920.00

 

IIRC, it's the Sylvania 2721. Available from your local autoparts store. (i.e. Pepboys, Autozone, ....) The base of the 2721 is different from the OEM but will work with a little bit of creativity. When you compare the 2 bulbs and look at the base you'll know what I mean.

 

Thanks, do you happen to know if one or two are needed for a 993?

 

I believe you'll need 2 but I may be wrong. The bulbs are cheap enough to keep a couple of spares.

 

You can get the bulbs with the proper bases from most German auto supply stores. VW/Audi, Mercedes, BMW, Porsche, etc. all use VDO gauges so a 10-pack of 0.9w bulbs (964.641.920.00) made by Jahn is around $5USD.

 

You do need two bulbs.I didn't know you "had" to remove the wheel to get the tach out when I did mine.All I had to do was move the wheel alot.It was really pretty simple.