78 XJ6L voltage stabilizer

Does anyone know the location of this unit? It is shown in the wiring diagram, but I have yet to locate it in the car.

I do not find anything called voltage stabilizer in my wiring diagrams or manuals. Can you give us another hint? What does it do; what circuit is it part of?

I recall someone posting about a voltage stabilizer in the earlier XJ saloons (Series I or II) that was located on the backside of the instrument panel that was used for the instruments and gauges. I suspect that a search of the archives will turn something up.


Paul M. Novak

1990 Series III V12 Vanden Plas

1990 XJ-S Classic Collection convertible

1987 XJ6 Vanden Plas

1984 XJ6 Vanden Plas

1969 E-Type FHC

1957 MK VIII Saloon

Ramona, CA USA

Hi Rob
It’s called a Bimetal voltage stabilizer, number 64 in my diagram,and is in the instrument power circuit. I believe it maintains proper voltage to the instruments, which, in my case, have all suddenly gone dead (all instruments except the speedo, which on this car is still mechanical)

I’m not familiar with the Series 2 cars, but I suspect that the voltmeter, OP gauge and tach are not powered by the voltage stabilizer. That might mean that a common source of power to the tach, the voltmeter, the OP gauge, and the stabilizer has gone open circuit. Or not…just a thought.

Ahh, found it.
Its on the back of the instrument panel.
Should have 3 (green) and 1 (light green / black) wire connected to it.
Apparently some of the instruments require 10 volts. Water Temp and Fuel if I’m reading the wiring diagram right.
Double click on the picture to zoom in.


it is sittinig on the back side of one of the small instruments. I made pictures that are in the albums http://www.jag-lovers.org/include/iv3.php3?zx=SdAEzw4IiM8ED8ZK%2FZnkxwXHDwWencoEzgcYtq2j3L1HN6OavET8PwvO2gpCvAwPi5jc98kfRd3dxDz4QPvS1Qw3CUz81dj998kfQdTHBkW8CxTZ1PdC9kk21doFMQo%2BMdrPBUD2QjzKyw4FxUk21pm7Bd1TRouZ2iX7Ghjf3uZJyRI8urbXK88nQdy7DhYCHSGqtuAC6CoBqbgCFsgm85ibyBjbKR%2FAruc2CSEQq%2BDcIusoG9%2B33BjZGyes3sv3yQ4ArLLXSAIqENbP7RT%2BSxyrt%2Fs4yyYGst%2FXRdlHPsm12R8GI%2FOYm8gYBzon36rlB90a85ibyRa8CwOZqrw1Akw7o533C8wJMJ2eyAIHEQSen89M0BL%2FmJnOAw8PAZaWxgTJOvCh. Not sure how RHD - LHD relates to the mounting place.

Good luck


75 XJ6L 4.2 auto (UK spec)

Unfortunately, Jason’s car lacks the magnificent Series 1 Fascia, which is what this diagram refers to. Jochen’s post shows the location on the Series 2.

That’s it! Easy, once you know where and what to look for. It is on the back of the volt meter (lower right in my LHD car).
Many thanks for all the help gentlemen.