So, I have an 88 240DL and the speedo doesn't do what it should all of the time.

Wondering if anyone could assist. I pulled the cluster out of a 240 at a scrap yard to experiment, but it was damn cold and I just saw a bunch of wires...I gave up.

Sometimes when I flick the plastic really hard it resumes working, and sometimes on a long drive it just works after about an hour, but in town the speedo just seems like it's trying to tell me something other than how fast I'm going. Additionally, my odometer is probably way off at this point.

Would replacing the entire cluster with a different one possibly solve the issue? I don't care what the odo says, I just want to know how fast I'm going.

Thanks!

sean

 

There is a good chance that re-soldering the connections on the circuit board on the back of your instrument panel would fix things.

 

Is that a messy job? What's the circuit board like? Lots of connections? Any in particular? And, to get to that, I have to remove the panel and the wires, then the panel comes apart?

Thanks Pierce. (Sorry so many questions)

 

getting at the innards of the inside of the speedo...

Electronic Speedometer Notes

 

Pierce, I appreciate your quick response, but I'm not sure that that page quite helps me. The console is already disassembled and I'm still not quite sure what specifically I ought to be soldering. Sorry to be so difficult. Thanks again.

 

basically, resolder everything thats soldered, on both the main instrument panel board, and the boards in the speedo. inspect for swollen/leaky capacitors, and replace any that look suspicious.

 

Have you checked the sending unit to make sure that there is not a frayed or broken wire. Also is the connector clean and not damaged by salt and dirt.

 

Yes check the sending unit on the differential. On my 240, all I did was touch the wires right after the pigtail on the sender unit and they snapped right off. Just had to crimp on some new connectors!