very strange things

been working on my 83 gti and it has a few niggles

i think they are all related so will list them

rev counter does not go above 1500 and stops totally when lights/dimmer is on
when lights are switched on mfa goes totally dim
can turn ignition on(not engine)with headlight switch
this issues also affect oil warning light
reverse lights dont work

clocks? fuse box was changed?  help!!!!


any ideas as i plan to investigate at the weekend

thanks

simon

Sounds like a bad socket or earth, check the clock unit itself for breaks in the tracks, but my bet is the earth which you can check once the dash unit is out.

Also I think the MFA earths with a strap on the carb, from what other people have mentioned.

Yes defo check the earth lead on the engine cam cover, it generally snaps as it enters the crimp that would cause mfa rev counter and instrumentation lamp to do what you are saying, the ignition via head lamp switch is probably a symptom of the same thing so fix earth first before you go hunting that one ;-)
reverse lights could be the switch is not pushed onto the gearbox correctly or the wire has snapped at the rear plugs? are your brake lights coming on ok?

seems as if we found problem today,somebody had done some diy to get things working as some circuits on clocks are u/s

had run ignition feed onto clocks which was interfering and earth pin was missing

new clocks and a bit of remodifying then hopefully be all sorted

thanks for advice!

si

mmm crazy wiring me thinks :-) probably had an earth problem and didn't quite know how to fix it! glad you found it!

very crazy indeed!

had pulled feeds off plug to clocks and soldered directy onto board…

just got to get clocks now then figure out how easy it is to remove speedo head as i dont want to lose mileage