Power steering sorted out now - the electrics are causing trouble.

Tacho dies and oil warning light shows. Battery found to be over charging - big time nearly 17 volts. Fries dashboard.
new (used) instruments and new regulator installed - all fine for a couple of days. Then Tacho dies and oil warning light shows. dashboard has some kind of regulator in it which was also fried in first instance

Does anyone know what may be causing the voltage fluctuation?

Could an alternator override a regulator and overcharge anyway? This is a logical possibility but it sounds far fetched.


Also if the seal foryour sunroof is split or worn take car to park with the nose of the car pointing downhill, especially if expecting snow. Otherwise water will sit in the sunroof well and eventuallu spill over to flow down the C pillar and be absorbed by the frankly astonishing amount of foam rubber under the carpet. Furthermore: Be aware that due to the "frankly astonishing amount of foam rubber under the carpet" you are unlikely to notice any moisture in the carpet until about a gallon of water has leaked into the car. the carpet gets heavy enough that it was a two man jobe to get it out of the car!

 

On most cars, the cause of the overcharging of the battery is a voltage regulator of some type has gone out. Most of the time it is built right into the alternator. Not sure with Audi's but it's a good bet.

 

Thanks for the suggestion.
Fortunately (?) the bosch generator has a separate regulator. This has been replaced.
In the words of Led Zeppelin - the Song remains the same.
I have heard that an overcharging generator can "override" a regulator.
Either that is what is happening or maybe there is an other subversive regulator/converter/transistor/actuator/whatever which is somehow interfering with the charging voltage.

 

Very odd situation, are you sure the alt has the correct diameter pulley? It seems strange that it is continually overcharging anf blowing things out.

 

yes it is weird. The generator/pulley is the factory supplied one that has been on teh car all its life (to my knowledge). Putting a new generator on tomorrow we'll see what happens.
I am convinced that something else is quietly contributing to the mayhem.