Today: Diagnose Those Dials

Dear Car Talk

Dear Car Talk | Jun 02, 2015

Dear Car Talk:

I have a 2000 Mercedes E320 with 144,000 miles. The temperature and clock dials on the dashboard stopped working after the warranty expired. I went to the Mercedes dealer, and he said it was very costly to fix it. So for the past nine or 10 years, I had no temperature or clock dials. But when I shipped my car from Florida to New York and loaded my car with clothes and stuff, I noticed that the temperature dial started to work after I picked up the car, and there was some indication of time. But when I unloaded the car, the temperature dial worked for a few days, then stopped. Then when I shipped the car back to Florida three months later, the temperature dial again worked when the car was loaded, but when unloaded it stopped. Please give me some reasoning for why these things would work only when the car is loaded. What do you think is causing this? Many thanks for any help.

-- Patricia

Gee, I don't remember exactly what your instrument cluster looks like. I know it has an engine temperature gauge, but I can't remember the clock. Maybe the clock is a digital readout?

In any case, I think what's happening is that when you put a lot of weight in the car, it's changing the geometry and reconnecting a wire that's broken. Most likely, it's a tiny broken connection in the circuit board on the back of the instrument cluster.

And your dealer was right. The instrument cluster would be expensive to replace. Unfortunately, if your engine temperature gauge isn't working, you won't know if your car is overheating, and if you continue to drive it when it's overheating, you could turn a $20 hose-clamp problem into a $6,000 melted engine.

So, while you've been fortunate for many years now, your luck might not hold out. Here are some options:

You can look for a place that repairs these instrument clusters. There are people who know how to re-solder the connections that tend to break on these clusters. You can find them online. The cost is somewhere between $100 and $200, plus shipping and labor to remove and reinstall the cluster.

And since you'll need to send out your instrument cluster, you'll need a repair shop that can help you. The dealer won't want to be bothered with this, so you'll have to look for an independent shop that specializes in Mercedes or German cars (try searching at

Alternatively, you can ask your independent mechanic to help you find a used instrument cluster. The price will be about the same, but your car won't have to sit for a week without an instrument cluster. Of course, a used one could have the same problem yours does, so you'll need your mechanic's guidance. And some luck.

Then there's the cheapskate solution -- the one I'm sure my brother would have opted for: Just drive around with your clothes and stuff in your car all the time. The upside is, if you spill some pasta sauce on your shirt during lunch, you can just run out to the car to get a new one.

Come to think of it, I'm going to start doing this.

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