Very weird electrical problem at the dash

[epowell]

I get consistently the same problem again and again > which is this:
Normally with the key out, the analogue clock is clicking away...
KEY ON and TWO things suddenly happen:
1) the clock STOPS
2) the Temp gauge blinker blinks once then stops

PS - I should also mention that I have recently fully cleanup both GROUND CASTLES.
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[epowell]

Well I found the problem, but now not sure what to do about it... the issue seems to be with 'dash light dimmer switch' which is right below the headlight switch. When the dimmer switch is rolled OFF and KEY IS ON, then the clock stops and the blinker just blinks once then stops >>>> now if I roll that dimmer switch to ON (KEY still ON) then the blinker blinks nonstop and the clock starts again. What's going on here?? Is there a SHORT in that dimmer switch? I noticed that all last year this dimmer switch sometimes worked sometimes didn't work... Perhaps I should just replace that whole switch unit, if they are available?

PS - Why would this dimmer switch be somehow DISABLING both the clock and the temp blinker, but then allowing clock and neverending blinking when turned on?

Seems they are only $10 --- hopefully they are available here in Czech https://www.brickwerks.co.uk/headlamp-switch-t3-non-dim-dip.html
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[crazyvwvanman]

I suspect the dimmer switch aspect is a bit of a red herring though it helps point toward the likely real problem, an inadequate ground for the cluster.

I often modify the cluster ground setup is early vans because of issues they have. In essence I double the ground connections and make them direct to metal near the cluster. I've written about it in various places and times.

VW changed the cluster ground during some 84 models and all later vans.

All traveling vans should carry a good spare headlight switch IMHO, as well as a spare good ignition switch.

Mark

[crazyvwvanman]

The early wiring has 2 brown wires to the cluster 14 pin edge connector. Only 1 of them is the actual cluster ground and the other is where other dash stuff shares the cluster ground. Bad design, as VW came to realize.

[epowell]

[crazyvwvanman]

No. You missed the prime objective. The prime objective is to prevent other things from sharing the same ground wiring as the instrument cluster blue foil circuits.

Mark

[epowell]

Ah... OK > I see now what you mean. So I will go out and do this --- and let's hope after that there will be some improvement.

I had checked that #5 brown wire recently and it is a working ground, so I see no problem with using that wire to ground the hazard lights... and I will run the other 2 grounds to a fresh known ground.

Before I do that I am going to put the temp gauge send wire (from the HEAD) into a put of almost boiling water ...and see how the gauge reactes and how quickly --- make notes of this --- then make this wiring mod. and repair the sender in hot water done in exactly the same way.... look for differences.
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[epowell]

So I just completed this MOD. > ...then tested "KEY ON" and there is no noticeable change or improvement. unfortunately.

I ordered today a new headlight switch (as well as a new ignition switch for good measure) - but won't get these until Monday.

In the meantime I will be testing various points on the console with my multi-meter... a friend is guiding me thru that because I pretty much haven't a clue
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[epowell]

Solved the clock/blinker weirdness! All I did was to remove and reinstall this little plastic nipple behind the clock!!!

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[epowell]

I can't say 100% for sure yet, but it looks like my temp gauge is now working properly... I think that the grounding mod. was the issue.
THANKS MARK!

For sure now I know that coolant IS circulating - rad is now getting hot.
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