Breaking News! This just in! Another gremlin surfaces. The battery is fully charged. The alternator puts out 14.58 volts measured at the battery. Does it know something that I don't?

 

The B+ post ( the big one ) on the alternator after the voltage regulator should read about 13.5 volt . You are reading the same thing at the B+ terminal at the battery above the battery storage voltage . Looks like a voltage regulator mounted on the alternator . 120 amp not cheap vs. normal 90 amp . You can have the auto parts store check this on car for free in 5 minutes . If not addressed it will cook your battery . Keep in mind the current state of the industry is they put out junk " reconditioned " alternators that can fail before you get out of the door . Have them spin it up first on there machine before you go through the trouble of replacing it with a bad out of stock unit . Then it may fail the next day after you replace it . Recommend just replace the " new " regulator to save some money for the rest of the alternator is a very robust design . The center terminal screw to get the bushing ring off may be welded or stuck so it may hang you up . Plan accordingly . Check your brush wear / mileage . The pivot bolt bushings toward the engine block were pinching on mine and had to file the shoulder of the bushings down for reinstall clearance . May have to use a large screwdriver to free this up to get it out . Can remove the alternator unit from the top . Don't forget the smaller control wires .

 

Went to the local CarQuest store for an in car alternator/battery test. No Joy. Electrical system OK. Red battery dash light remains on and the Trac fail and Anti-lock fail have joined the light show. I don't think they are related. The Trac/Anti-lock warnings have been intermittent for years. Other than that everything running fine.

 

I'll get with you in the morning with the 3 annoying display lights Ref. wiring schematic and practical things .

Thanks , Parker

 

Gremlin struck last night out of the blue on my 1995 XJR, battery light came on, volt gauge when to half way normal 10.5 - 11 V. I turned off AC, radio and lights to save battery but no difference in gauge, so it wasn't the belt ( which it wasn't) It sounds like the voltage regulator? What do you think where should I start?
Snowball

 

Snowball , is it a true voltage problem or an indication problem ? Jdenglish1944 is a indication . The alarm sounder will sometime short out and is tied into the regulator . You can remove it's connector behind the right headlight down low with connector pointing up . There are some other item's I'll look up . Did you get rain during the anomaly ?

 

Wasn't raining when light came on, but had rained early in the day and I was out in the car.
Snowball

 

Snowball , did you have to recharge the battery in order to get the battery up and fully charged ? This splits the problem in half .

 

Sorry I will do that now and let you know.
Snowball

 

I'll break down this print later in the day for there is more involved then what it shows .

 

Charged battery up , problem remains Gauge at 11 volts battery light on as soon as you turn on ignition. Found sounder wiring jacket seems to be facing back toward engine compartment, should I disconnect the jack? I do have parts car as well.
Snowball

 

Yes , just disconnect sounder wires for now and look at gauge .

 

Work in progress . First draft . Watch for edit

 

Disconnect sounder, no difference in gauge or battery light How should I check altenator output
Snowball

 

duplicate post

 

On the B+ terminal ( large wire ) it should read 13.8 to 14.5 volts to ground which is above the fully charged battery of 12.77 to ground . Running pulleys and such so be carefull . No need to remove terminal connection just scoot insulation boot back

.http://tidewaterfleetsupply.com/Delc...leshooting.pdf

 

120 Amp voltage regulator with monitor Denso # IN435 or Jaguar # JLM-11144 replaces DENSO # 126000-1200

Mine was consumed by a backwards battery hookup

Also used on: ISUZU STYLUS 1992-93, JAGUAR 1993-1997, DODGE COLT 1991-92, ASTRO, IMPULSE, GEO STORM 1996-2000 Asuna (1993-1993) , Geo (1990-1993) , Isuzu (1990-1993)

https://www.ebay.com/sch/i.html?_fro...-1200&_sacat=0



VOLTAGE REGULATOR JAGUAR VANDEN PLAS XJ12 XJ6 XJR XJS 1992-1996 | eBay

 

New alternator solved the problem, Thanks for all your help.
Snowball