[&:]Hello, I've got a 1989 300SE with a frustrating dash & console illumination issue - kind of a long post - pulling my hair out and would love to hear back fromsomebody that knows these cars.

First of all, the car has been sitting outside for 5+ years with no engine/trans. The lights in question worked fine before it sat. I've just installed a new engine/trans and the car runs & drives great! Only thing is, no dash or console lights.

I've pulled the cluster and found the rheostat to be bad & the red fuse blown. When I jump the rheostat terminals on the cluster, it instantly blows fuse #11 (illumination, license plate lights etc...). I noticed that the the inboard rheostat post is a ground when it should be power.

I've pulled every bulb & switch controlled by the rheostat throughout the entire car & also disassembled the cluster and nothing looks faulty.

I havetraced the issue down to this: If I have every switch & bulb plugged in except for the two large bulbs at the top of the cluster (not the turn signal indicators but the bulbsoutboard ofthem - called "3W dash light" in the pic I found online) the remainder of the lighting in the circuitworks great and the rheostat post is a positive terminal again. As soonas I installeven one of the two large bulbs the terminal turns in to a ground again & pops fuses. I suspect that something is going on with either the gray & blue or pink & black wire that comes out of the center plug on the cluster behind the speedometer, but I can't tell where it leadsunder the dash. I've got a wiring diagram off ALLDATA but it's not helping much.

Any ideas??? I'm about to drive the car offa cliff after two nights of disassembling and reassembling my dash, console, sunroof switch & rear power window switches!

Thanks, -mckowalski

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check circuit board line for the 2 large bulb, there might be a short in that area that makes the fuse pop. try also to check if the bulb holder is in proper condition.

I am having a simulair issue. I took my car (1988 560SEL) in to get a new stereo system and alarm installed and that night my lights didnt work on my dash or console. I took it back to find out what Car Toys did and then they broke myonly key in the ignition. SoI was too pissed to let them touch my car.I took it upon myself tolook over everything and found out that my grey and violet wire provide the power for the lights. When I looked at the back of the speedo the grey/violet wire went to post 1 with no post to connect too on the speedo. The part that provided power for the W3 lights was where a gray and blue wire was in the 8 post. I applied power from the grey/violet to the grey/blue and it blew the #11 fuse. I then switched the 2 and now the cluster lights come on but no power to the center console... still trying to find that out. I knew my lights have power cause the new radio has the instrument wire to dim the lights on the stereo. If you know how the wiring should be or what the grey/blue wire goes too please let me know. I know the plug is not flipped cause the #4 and #6 still control the turn signals.

Thanks for the response cool. After removing every bulb in the system and quickly cleaning the connections, everything worked fineafter reassemblywith no fuse blowing. I also cleaned-up the conections on the circuit boardof the cluster. I'm not really sure where the problem was but everything's been working great since then - knock on wood.
OnCoolcruet's 560SEL lighting issue.... I'd check the ashtray light & make sure it isn't out of place and grounding out on something? Maybe check your shifter light for the same prob?
Here's a link toa page that's got a little more info on interior lighting etc.. http://articles.mbz.org/instrument/