Fuel & temp gauges go mad. also wobbly speedo below 20mp

[nickh]

Hi.

I have noticed my fuel and tempurature gauges seem to go up and down like a yo yo, on many occasions, whilst this may be funny to watch for a while i can't help but thinking something is wrong? any ideas?

Also my speedo cable jumps around below 20mph, I cannot see a speedo cable coming through the engine bulkhead though.

its a 1992 230e w124 series.

 

[jaymanek]

With the temp guage, check the switch located on the head. Mine did this and it was just a dirty/rusty connection with the wire.

Petrol, guess its the sender...


But now im thinking, if theyre both doing this, then maybe its the wires behind the dash, could be a little corroded or loose......

 

[Kinky]

My temp guage goes up (to the max - 130+) and down (to 80+) like a yo yo as well.

Dealer checked it all out and quoted me £350+ (from memory) to replace the dash as that's what they reckoned it might be.

Admittedly I don't have a problem with the fuel guage (except it goes down way too quickly), and I've not yet looked into the wiring, bad/rusty connections, etc ...

Perhaps a job for this weekend ....

 

[jaques2k]

I got the same prob with the fuel gauge, but my problem was a crack in the circuit board behind the gauges. Just solded the circuits tight again, and no problems after that! Does anybody by the way know what colour the tachometer and temp. gauge wires should be and where the sender is located on a early 1980:s 6-cyl petrol engine (I will get that engine number asap)?

 

[mercmush]

I thought that wobbly speedos especially at low speeds meant that your speedo cable had been changed or fiddled with ?

 

[jaques2k]

Yes, the wobbly speedo was in an earlier posting also, there the answere was that the speedo cable needs lubrication or replacement. This is of course only in those cars wich has a mechanic speedo.

 

[durado]

I had the same problem on my 84 300D ... somebody had taken apart my inst. cluster. One of the traces had gotten scratched, but the metal chasie of the speedo would make intermitent contact and peg my gauges and then they would drop. I took the cluster apart and inspected it. When I found the broken trace I soldered a wire from the begining of the trace to the end (by passing the trace). Also, check your ground. I've heard of the same problem being caused by a bad gound to the inst. cluster.