99 Jaguar Vanden Plas

Car starts fine and seems to be running fine when I rev the motor at all the dash lights go black and my headlights blow out and become burned out lightbulbs. what could be causing this ?

 

Voltage regulator, which is usually integral with your alternator.

 

I will pull the alternator and bring it to the alternator re-builders shop just down the road tomorrow

 

you can tap into the glove compartment light socket and with a digital meter watch this spike in voltage

You can solder in some test leads to make the test confutation work easier

The voltage regulator can be changed while retaining the original alternator

the alternator brushes and commuter should be fine after inspection while you have it apart

The regulator is part # INxxx ?

https://www.jaguarforums.com/forum/x...-fixed-106944/

 

I tested the votlage at the battery when idling and it was 15. something, that seems kind of high to me, I wasnt able to test it when i rev as I am working on it alone, i will try to see if I can get volt reading out of the glovebox light, i should be able to see the volt meter from there, thanks

 

Since the regulator is usually mounted inside of the alternator, why not let the shop renew all that stuff and get it over with?

 

I'm just going to have them replace everything that needs replacing while they are in there, new carbon brushes, new bearings, new regulator, I hope that solves the problem

I thank everybody for your input

 

15 is usually considered on the high side of 13.5 to 14.5

overcharges and cooks the battery

some people let it go in this condition but in your situation there is evidence of it going higher and causing damage to some expensive different ECU's

yours is unstable so on throttle up no telling how high and testing not necessary with the information you have at idle

 

Definitely sounds like your headlights burning out saved you from more expensive stuff being cooked by a bad regulator.

 

The headlights burned out when I went to the store last night, and I tried to drive home with high beams but they blew out half way home, then I put new bulbs in and they blew out after being on for five seconds. That's when I started scratching my head. Hopefully the alternator tests bad tomorrow and I will know what's causing this mess. The car has been trouble free driving for five years so I guess I was due for something.

 

What year model is it, by the way?

 

99 Vanden Plas

 

Here is a link for your car's basic electrical components:

https://www.ebay.com/b/Charging-Star...e+Sedan+4-Door

You car's alternator new is only $207.75 with shipping for free.

The kit to renew your alternator's regulator and brushes is $44.99

Hopefully your rebuilder will not be greedy, because if he charged me near the price of the new one, I would go for the new one.

 

I had problems with Ebay sourced regulators from 2 different vendors

They would fail in more ways then the original regulator

A brick store has more at stake in ensuring a happy customer in my opinion so they would be more concerned in addressing bad stock and not just putting it out there.........next

 

Thanks for the info, I been using this shop for all my alternator and starter rebuilds for years, its generally $50 or less each time I visit, and they have always worked perfectly when I re-installed them. If they don't have the parts for this particular alternator I will order them from there and have them install them. That way I know its done right

 

You installed your own regulator into your alternator?

 

Hopefully I wont have to resort to that and my re-builder shop has what is needed

 

OK, glad to be of help

 

If the headlight bulbs blew so quickly, you had a serious over-voltage coming from the alternator. This can only be due to a bad voltage regulator not controlling the voltage, i.e. having a short inside it sending full current to the alternator's exciter coil. In this case, the alternator voltage can go up to as high as 20-30 Volts. Do not go for the cheapest Ebay (fake?) regulators but get one from a reputable supplier. I get Denso alternator parts here: https://store.alternatorparts.com/in...regulator.aspx

As for the engine ECU and other modules, hopefully they are not damaged as they usually have in-built over-voltage protection.

 

Yes , easy to do

The auto parts stores will spin test it for you on a machine

But I found a salvage car to use one from