My wife's E300D has been whining about a defective bulb. I knew the left half of the speedometer was burned out, and I replaced it yesterday (really easy, by the way) ... but it's still complaining.

I noticed that the CCU doesn't light up at all with the headlights, so my working theory is that's what the computer is complaining about.

Anyone got tips on how to replace the bulb(s) in the CCU? Googling didn't turn up much.

Thanks.

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Lots of diesel W126s in the past
Current: 1991 Toyota 4Runner with an OM603

Got a pic of the unit? On the facelift 210s you slide out the CCU with radio keys, then there is a single bulb in the bottom of the unit, a couple of bucks at the stealer.

That said, the computer only monitors exterior bulbs, so it's not the CCU.

Carefully inspect each of the exterior lamp assemblies to be sure they are lit. A common one that is very easy to miss is the license plate bulbs, there are two of them and when only one is out you can't really tell without sticking your head in there to look closely. If that's not it, the tailight lamp holders and connections are the next common culprit. I posted a kind of process-checklist at BW in the 210 stickies section if you're not sure of the main circuits to follow.

Good luck, this kind of stuff can be really frustrating.

Great info, thank you. I'll go over the lights with a fine-toothed comb.

I don't have a picture of the CCU, but here's one that looks the same (radio is different on mine -- a cassette unit, though):

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Lots of diesel W126s in the past
Current: 1991 Toyota 4Runner with an OM603

Yep, that's the same CCU. Use the radio keys in the slots on the lower corners and there is a single tiny bulb in the middle of the bottom. If that's all you need just get it at the stealer, shipping will eat up any savings you might find online and they can look it up. It's about three minutes to change it...if you have the keys.