I have a minor problem with my gas and temp gauges. My temp gauge works for a bit while driving, but if I do any hard acceleration, it goes crazy bouncing up and down until I let off the gas at which point it falls to the bottom of the dial and sits there until the engine cools. My gas gauge has a similar problem of jiggling back and forth when I have roughly half a tank of gas. It works fine above and below half. Is this something that I can fix myself, and if so, what parts are needed?? The car is a 1987 560SEL.

The first thing to do is replace all of the fuses in the box! I have had more fuse problems with these than any other model.

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Benzmac:
Donnie Drummonds
300E
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM
OWNER OF MB AUTOWERKS .COM

That was the first thing I did, all the fuses look good, what next?

Your second post is a little unclear as to what you did. Benzmac stated "replace all fuses" sounds like you only looked at all. If the advice is to change them all, then change them all. Quite often the fuse or fuses may look OK, but time and corrosion have taken a toll. And if it turns out not to be fuses, well then you have peace of mind knowing you have good fuses in the block.

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Mike Tangas
73 280 SEL 4.5

Thanks for the advice, I changed all the fuses, although it didn't solve my problem, it is nice to know that I don't have to worry about fuses (for now). Unfortunately, the gauge problem still exists. Any suggestions on what else might be the problem would be appreciated. Thanks.

Sure you can fix it. You will need to know how it works and how to take it apart. From a wiring diagram you will see that the power and ground circuits for those two gauges are the same. You might assume one of these to be the problem (more likely than the individual parts). A gauge has three wires (circuits): power, ground, and a variable resistance sensor signal.

Before I disassembled anything I would try to verify my hypothesis. Since the power and ground are internal, the sensor signal would be an alternative. I don't off hand know the resistance of the engine coolant sensor, but I would read the thing and then substitute a known good resister of similar resistance and a good ground. Drive the car a see if the condition exists. If the condition continues the dash must be removed.

All the circuits can be powered individually but this is time consuming. The 126 dash uses the overlaying of components to continue the ground from side to side. Loosen and retighten all the mounting screws that pass through multiple components. Identify the nuts mounting the individual gauges to the printed circuit and loosen, retighten them also.

It is very common to have fuel gauge needles swing madly due to the sensor in the tank. It is uncommon for the temp gauge sensor to have this problem. Chances are good that a circuit common to both is weak. Either find it or replace the gauge section (after verification by substitution at sensor).