Electrical mysteries

[leewiffen]

69 912

After buying the car, I get the car on the road and the generator light is staying on. When I look at the dynamo the brushes have no spring and are wedged into the holder. Bingo methinks

So I got meself one of these...http://www.autoelectricsupplies.co.uk/p ... tegory/165 and fit it...still the same

Next stop a new regulator https://www.vwheritage.com/shop/1139038 ... amp-bosch/

Fit new regulator and by the way I'm using a brand new Bosch S4 001 battery

Partial success, now the light is going out but only after around 2000 revs plus. Prior to that it still glows faintly....I haven't done a voltage check yet, but does this point to fan belt tension ? It's tight but not like a drum, I can still affect it by pulling on it

Ahhh, but to throw another spanner into the works, which of course may have no relevance, added to this mystery is the fact that also on the dial that houses the generator light is the handbrake warning light....initially this was flickering and going off when you dropped the handbrake but then coming back on.....So I immediately thought dodgy switch..

Take out the carpet and rubber boot, tried to adjust the switch but no joy.....took the switch out and it was busted so disconnected it altogether. Light goes off....thinks...problem solved, just fit new switch

Go for a drive, light flickers on and off !! No connection anywhere at the handbrake end as the wire to the switch which I removed is isolated.....so somehow the light in the gauge is getting an earth...or maybe not?

Oh, and another thing, whilst driving I think, I'll try the horn....very poor lightweight sound which does smack of poor earth as all the wires are connected, however it could be a poor contact in the steering wheel, or poor fusebox connection....

Two things done on the car that may have relevance...when I first got it, no indicators or hazards. Cleaned related fuses in fuse box with emery cloth, problem solved

New brake master cylinder fitted..

I must say I am leaning towards fuse box and that is my next port of call.

Oh I have also been up behind the dash to fit a new dash top and the big earthing point/ bolt near the offside bonnet strut looks a little corroded but very tight....difficult to get to without removing heater paraphernalia, but is this the main earthing point for all things such as gauges, horn, lights etc?

Any opinions, experience, ideas would be gratefully received.

[neilbardsley]

The dyno should kick in about 800rpm. You should be able to push your fan belt in about 1cm. I would suspect bad earth. Check voltage at dyno as you rev with and with Df and work back?

[Nine One One]

Reference your dynamo light coming on.
I remember there are issues with the ‘new’ type of Bosch regulators, and think the body had to ‘insulated’. Something to do with the outside of the body being live, when connected up the way it is with a VW or Porsche 912/356.

Somebody on here may have had a similar issue, especially on a VW. I will try and find the answer for you, but you need to make sure the Dynamo is earthed properly.

Check this Pdf out, as this is the same Regulator as you are using. I don’t think it was the one I was looking for but explains a few things.

Sometimes the issue is that the dynamo does not earth properly through the dynamo stand, and you have to run a better earth from it?

http://www.worldphaco.net/uploads/LUCAS ... ULATOR.pdf

Ian

[leewiffen]

I was wondering also if the brushes take time to wear in on a new dynamo, if from manufacture they sit square.......