Can anyone help with this odd problem. My problem is the horn blows it's fuse every so often so I thought that I would have a look to see what was going on. I looked around the dash board and the radio, could not see anything so it all went back as it was. The next morning I came down to a dead car, nothing. I have replaced the battery and now I have no ignition light, I have checked the bulb, I have checked that the battery is charging when the engine is running, checked over all the bits I looked at the day before and still no light. Can anyone help as it is driving me mad !

Have you checked your alternator? If one of the rectifying diodes has blown, it will tend to discharge back to earth through the windings.

If you disconnect the alternator,and then start it up and it runs off the battery, then the alternator is at fault and needs either a full rebuild (at minimal cost) or replacing.

OSD

Thanks but would this apply to a TDI as well?

It doesn't matter what vehicle as long as it has an alternator ... Series dynamos are slightly different, but they all work on a similar principle!

As I said, disconnect the alternator first and see what happens.

OSD