Instrument binnacle - colour coding of cables to bulbs

Hi Alan

I would check out the Earth connections under the dash (and all others for good measure) and strip and clean them up. Especially if it has been stood a while or shows signs of any moisture under the dash from screen or spindle leaks.

Failing that the Potentiometer behind the cluster runs some of these systems.

When you say Clock and Tach dont work, do you mean that the units themselves dont work (no time and no revs/speed) or do you mean the Bulbs dont work on those units? As per the thread heading?

Do you mean Tach as in Rev Counter / Tachometer?

If they dont work at all, have you any power feed to them?

If Bulbs i would go for Earths and Power Feed from the Potentiometer, i think from memory you can simply bypass the potentiometer but the Bulbs will shine full strength all the time and not be adjustable

I reckon i know someone who might havea known good Potentiometer available if that proves to be the case, although they are not mega bucks.

Sounds like you have the Cluster out already, if not i can post the correct Dash Cluster Puller Hooks and you can just drop me them back when done, saves cracking the clear plastic cover and annoying yourself!!! Not sure if you can still buy the Cover seperate.

Gav

This is usually a failure of the rev counter sender unit. Housed on the near-side of engine compartment. Looks like a diagnostic socket but slightly smaller in diameter.

Unscrew the cover and you will see a sender unit under the cover. Pull the sender out (have to be a firm pull). Next pull off the top cover to the unit, again a firm pull, might need a flat blade screw driver to help prize it open. You will see a waxed covered top.

Taking a small piece of A5 paper fold it into a quarter and sandwich the folded paper in between the waxing and its cover. Refit the sender back into the socket and start vehicle; hopefully the tacho may register. Try a wriggle test to see if that helps. The sender unit is not cheap. Other wise requires diagnosing.

Hi Alan

RPM indicator transducer fitted to side of  transfer box but with clock not working as well would point to power /earth or instrument fault

need multi meter for power check and earth (ground)  test wire run from negative post of  battery direct to cluster ground point   ( brown wire) connection

  same instrument fitted in W124 cluster ( local breaker )