Hi everyone, this is my first post in a looooooong time, as I've just rejoined the world of Polo ownership yesterday with this little beauty:

 

 

Absolutely delighted with it, 86k on the clock, remarkable body and paint and very strong motor. A real throw back to my first car, a mk2 breadvan almost 10 years ago!

 

However somewhere in the electrics there's a bit of a gremlin lurking. Here's the issue:

 

With the ignition turned on, turning on the headlights causes most of the guages to work incorrectly, the dash lights to go out and the clock to stop ticking. Turn them off again and everything returns to normal. Without the ignition on, but the headlights left on, this doesn't occur, although as I'm sure most of you know, in this instance only the sidelights are on drawing significantly less power.

 

I am guessing that there is some kind of faulty earth in the headlight circuit or a dodgy relay or something, but before I went taking everything apart (not difficult on these I know), I wondered if anybody else had experienced a similar issue and could point directly to a common cause of this fault and save me a bit of rooting around!

 

Thanks in advance, I look forward to getting back into the Vee Dub Club

Good to have you back!

 

I think you're on the right track with your diagnosis. I might be inclined to try another headlight switch because they're fairly cheap, easy to change, and can make odd things happen when they're not working right. 

Wonder if the 3-pin voltage regulator on back of clocks is dying? 

Headlights on with engine not turning the alternator will cause a fair voltage drop - especially if battery not well charged.

 

There's no relay in the headlight circuit. There's the dash switch and the high beam dipped beam stalk switch (in the wiper stalk body -operated by a plastic hook from the indicator stalk - I kid you not).

Edited 19 March, 20179 yr by dvderlm

Thanks a lot Yeti, great to be back!

I think you're bang on with the switch being defective. Turning the rheostat wheel causes the problem. I set the dimmer to the lowest position and headlights and dash instruments work as normal. Should be a quick easy fix then hopefully! New part coming from the bay so we'll soon see.

 

Thanks for your help, I'm sure there'll be a few other niggly things that crop up as I cover some miles!

17 minutes ago, dvderlm said:

Wonder if the 3-pin voltage regulator on back of clocks is dying? 

Headlights on with engine not turning the alternator will cause a fair voltage drop - especially if battery not well charged.

 

There's no relay in the headlight circuit. There's the dash switch and the high beam dipped beam stalk switch (in the wiper stalk body -operated by a plastic hook from the indicator stalk - I kid you not).

 

Interesting. I have heard of other instances of voltage regulators leading to problems with clocks on other cars. Is this a relatively simple part to get your hands on?