not any more!

tom w

Since I tightened the loose ground strap, the car now starts fine. However, there's a new problem: The coolant temp and fuel gauge are now both pegged at the upper end of the scale when I am on the hwy. When I'm stopped at a light, most of the time the 2 gauges are pegged but sometimes it jumps between pegged and normal reading.

Hey Tom, where exactly is the problem this time?:)

You don't know what I went through to fix the coolant temp and fuel gauge! I checked everything. The temp sensor is ok, the cluster has a good ground, the gauges are getting +12. The gauges work except it's indicating 80 deg and 1/2 tank too high. Turned out it was the gauge pod! I reseated the circular connector a few times which didn't help. I took it out, re-soldered every connection, found an almost melted copper trace and jumped it with a piece of wire, put it back and the gauges now read normal. What a PITA that was. What bothers me is the unlikelyhood of so many seemingly unrelated problems poping up within a few days. Hope this don't happen too often.

My guess is that they may not be unrelated. If the engine ground strap was loose, the only other path to ground could have been through the instrument cluster thus burning out that wire.
bb

That has crossed my mind. If a loose ground strap could burn out copper traces in the instrument cluster, I would call that poor design on the part of Mercedes engineers. If I am really curious, I could pull the cluster, buzz out the burned trace, draw a diagram and analyze if that is possible. Maybe next time I'm in there.

When I first saw the title I thought 'how does one get stranded with internet access?' :smartass:

I have internet access on my phone! :) As long as I have a Sprint signal, I can get help from this forum. :pleased::pleased::pleased::D:D:D

Well, you can call the ground burnout in the cluster a design flaw, but also keep in mind that when the car was new/less than 24 years old, that probably wouldn't have burned out, and definitely wouldn't have burned out as quickly.

Many things on these cars, like the vacuum lock system, can be seen as design flaws or poor design, but keep in mind that these cars are over 20 years old and it all still works. That seems to run counter to any arguments in my mind.

Then again, maybe you're right. :rolleyes:

Ahh life in the age of teckmology.:D

Got to love that EVDO Sprint service! 1 Meg downloads to a phone?? :D

OK I am done hijacking now.... carry on.....

any time to trace out the circuit and figure out why it burned? or is all working well, and you don't wanna mess anything up?

Sorry, didn't see your question till now, 7 years late. :D

Cluster has been fine since the repair and I have not done any tracing- sorry. Car sold to JB3. If JB3 saved the cluster, and if he post a pic of the repaired burned trace, there is a possibility I can trace the circuit on my 85, if both clusters are the same.

I did indeed save the cluster, where would I find the repair? is it right on back?

You'd have to take the gauge pods out and look for traces that I soldered.