I have an 89 240 and the instrument cluster lights went out. I think the rheostat is OK cuz the tranny and radio lights still work (and will dim using the rheostat) I pulled the cluster and the two bulbs at the top of the cluster and they did look OK. I did notice one wire on the inst cluster wiring harness was dangling (red and white I think) but there did not apper to be any spot on the cluster this could have attached to. My cluster does not have a tach. Is there anywhere I could ge a wiring diagram of this cluster ???

thanks for any suggestions/ help

Tom

DON'T hook up the red+white wire, it is for the tach as you may have guessed.
It will fry pretty much anything else you hook it up to.

I still suspect the bulbs. They're pretty small, though you may be able to test them if you've got an electrical tester with small-tip probes. With the cluster out, you might be able to test the bulbs easier if they are installed in the cluster. The cluster might have contacts big enough to get a test probe onto.

In my experience the bulbs go bad with the handling of removal from the cluster. Shouldn't be true, but I think after years of use + vibration, it doesn't take much.

The Haynes manual has a cluster circuit diagram but I wouldn't trust it to be complete or authoritative.
--
Sven: '89 245, IPD sways, electric rad. fan conversion, 28+ mpg - auto tranny. 850 mi/week commute.