Occasionally, none of my instrument lights will come on at night. I mean all of the interior switch lights and the instrument cluster itself are off. Sounds like a crusty relay to me, but I don't know where to start looking.

You did not mention what kind of car or year but, a very common problem is the rheostat or dimmer control which, also resets your mileage counter. It is not too expensive but, the intrument cluster has to come out since it is located behind it. Once you have the instrument cluster out, you can figure it out.
Good luck!
J.H.
'86 300E

Seems like everyone forgets to put in what car they have. Sorry. It is in my signature, but I have to remember to check it.

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1985 380SE, 100k miles

Go back to the fuse box. Pull the fuse, clean the contacts and put in a new fuse, even if the one that is there looks OK. There have been a lot of this type of problem related to faulty, corroded fuses. I don't think there is a relay for dash/instrument lights, but who knows!!??!?!

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Jeff Lawrence
1987 300e Sold
1989 300e
2000 Dodge Grand Caravan SE

After checking/replacing the fuse as jeffsr suggests, if you still have intermitent dash light you can try working the potentiometer (dash light dimmer) stop to stop. Sometimes the contacts get corroded and a good twist will clean the contacts and the dash lights will work.

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Mike Tangas
73 280 SEL 4.5

My 85 does not have the dimmer. Must have been one of the 86 year feature additions.

....now that's odd. I too have a slight problem with my instrument lights. They have always seemed a little too dim for my liking, even with the rheostat full up. I pulled the cluster out this afternoon with a view to relamping and cleaning the contacts. I found all the 1.2 w lamps working fine but the rheostat was not what I expected to see. I thought it might be the old wound wire resistor coil type I have seen in plenty of cars in the past but no, this was a tiny, solid state board and a very small microchip and the reset shaft passing through it ! What on earth is all that lot doing there, simply to dim a few lamps ? Clealy, I have no contacts to clean or lamps to replace as Jeff Lawrence rightly suggests in most cars, any ideas what might get these lamps back up bright ?

My lights that illuminate the transmission gears are out. Is that bulb hard to replace?? Where to begin?

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'89 420 SEL
'90 300 SEL
'68 Olds 88 Convertible
'84 300 SD (sold it)

No problem provided you are careful. You will need to find a wide plastic ' lever ' and gently push forward the wood trim about 3/8 inch and it will then lift out of the cut out. It is held in by rather flimsy plastic catches stapled to the trim. Once this is out, the lamp ( bulb ) sits in the same holder as the one for example in the ashtray, just a push fit. This single lamp then illuminates the light plate and diffuses light across the selector plate. I know the wood trim is not cheap and needs great care when removing. good luck...

Thanks for the 'dimmer' tip who ever posted. I found in my '89 300E the odometer reset button actually doubles as the dimmer. By turning the button clockwise or counter-clockwise you can change the lighting condition of the instrumental panel. It was too dark and I didn't know how to turn it brighter.
Thank you!

Steelclock
'89 300E

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ain't these just great people ? :)

Andy, is your instrumental lighting condition brighter now? Did you have to fix a lot of things?

Steelclock

Hi steelclock, Well I pulled out the cluster and replaced every 1.2 watt lamp I could find that iluuminates the back of the dials with new ones. Whilst I had it off, I also cleaned with contact cleaner the shaft that runs through the dimmer/reset switch. As I said earlier, this is a solid state affair so there are no wire contacts to clean and as the dealer here wanted over $120 for this piece, I though this a little expensive just to troubleshoot. I also noted the previous owner had soldered a parallel lamp installation to the red battery warning lamp and used a blank red annunciator window at the far right of the lower strip. This I removed as I dont really need 2 red lights to tell me I have a battery faulty. I reassembled the whole lot and waited until it got dark ! Wierd thing is, it is still the same. I am comparing it with my 190 which has the same 1.2 lamps and is a lot brighter, perhaps this is normal for the 500SEL. I don't know. I found a dimmer switch in the scrapyard during a recent visit but is only has 2 contacts on the back and is the old wire wound one and clearly designed to fit another auto. Perhaps I ought to accept it as it is ? :confused: