w124 300e tachometer frustration
 

Hey everyone
I've enjoyed the info from this forum for a while but this is my first post.
I've read almost every post about tachometer malfunctions but none of the solutions have worked for me. Here's the deal...

Removed the instrument panel to change bulbs, accidentally touched 12v lead from clock to car (spark and a loud "pop", didn't disconnect the battery, rookie oversight).
Ever since then the tach won't work and the clock only works when the car is off. I've replaced all fuses including the 10amp near the Klima control. Also, the a/c
compressor doesn't work now (read in forum that the system reads from inputs such as the tach).

Is there anything else that could have caused the problem with the tach? Thanks in advance!!!

Matt Anich
1987 300E

Make sure there is 12V on the lead otherwise the wire is bad.

I did this once too, a long long time ago. Solution ended up disassembling the entire cluster, and discovering a burnt trace that had lifted off the circuit board and separated. The fix was to solder a short piece of wire to jumper between the two connections.

Anthony

Couldn't find any missing connections on the circuitboard, also the 12v lead was dead... couldn't trace it to its origin but i did run a lead straight from the battery and plugged it in. Tach still doesn't work. Any other ideas or is it time to shell out at the shop? Thanks everyone for all your help.

Matt

I have an extra tach...
 

Let me know if you are interested, I will let it go for cheap...Send me a PM.