A few weeks ago both my low beams went dark, at that moment there was a "crackle" on the radio....so I know the filaments have blown. I look down at the volt gauge and it reads about 16 t0 17 volts in the red but immeadiatly starts to fall back to the normal 13 volt reading.

Nothing else electrical appeared to have blown.

So this is a voltage regulator problem..yes, no?

Cannot really see how a bad ground could cause an over voltage.

Since this happened I've seen this happen at least once more, by carefull observation of the volt gauge...only in daylight as I don't want to replace the low beams until I get a fix on this.

So do I just pull the alternator/regulator assembly and get it tested...bearing in mind this is an intermittent problem...may have been going on for sometime as I don't do a lot of night driving...or....

Any suggestions as to any tests diagnostics I can use as a starting place very much appreciated, as the garage is real cold but I will raise the front end and drop the alternator, if this looks likely to be the cause here !!

If it is the alternator/regulator assembly, any suggestions on a good rebuilt/new supply source?

Thanks,

Rob.
2006 X type Sport Wagon.
1987 XJ6 DD.
1994 XJS 6.0 Convertible.

 

Hmmm. I can't think of any possible fault except the voltage regulator.

Great to have the alternator tested but, as you imply, the test will reveal nothing unless the fault is present at the time.

I would just go ahead and replace the regulator. Or have the alternator rebuilt....which would naturally include a new regulator....if you have a local rebuilder (many towns do!).

Otherwise buy a rebuild from whatever parts house you usually use. IMHO all off-the-shelf rebuilts are an equal gamble no matter what the name is on the box.

Cheers
DD

 

Thanks Doug,

Didn't know the integral regulator could be replaced....any suggestions for sourcing one?

Rob.

 

OK Doug. Seems everyone has them.

Think I'll check out a new/rebuilt alternator as well.

Thanks.