Hi all,
While working on my instrument cluster I believe I have blown the fuse responsible for dash backlighting- the lamps/cluster works on the desk but when I plug it in there is no backlight. Do you know which fuse covers the backlighting and rheostat and what is the replacement model ?

Also, anyone know which one drives the wingmiorrors ? This is another project on the list.

 

Fuse number 4 in main fuse box under steering wheel. 10 amp (UK rating).

Mirrors, fuse 8, main fuse box, 3 amp rating.

 

Thank you Greg!

 

Matt
Keep a lookout on ebay for one of theese. It has most of the systems in the HE very well exlained:
https://www.ebay.co.uk/itm/253042432...3ABFBM-MKHnPNj

You can also buy a full workshop manual with this incorporated in it.
https://www.ebay.co.uk/itm/134686822...BDY8Q7EGYVPY4J

 

This is brilliant thanks.

 

So it wasn't the fuse...I think I will need to consult that manual you recommended...!!

 

Start by looking at, and possibly bypassing, the rheostat.

Paul

 

Matt
There is a good chance of a dead short to earth in the actual unit being powered. Try isolating each item being powered by the relevant fuse, one at a time, and then testing. It should be a matter of just unplugging one at a time, somewhere between the fuse box and the item.
Fuse 8 powers door locks and mirrors, fuse 4 panel instruments and reversing lights.
As Paul suggested, the easiest way to isolate the panel lights is to rmove the shin trim and pull the leads off the rheostat.

 

I have tested the cluster backlighting on the desk at home with no apparent grounding issues, plus there is no power to the relevant pin(s) on the clip in loom in the car.

So I suspect either the rheostat has suddenly stopped or possibly the switch (in the headlight control?) which turns on the dash illumination. trying...!

 

this is a sensational resource. The backlights are actually fuse 7 (I believe 4 is the warning lights and gauges), which was bust, physically bust that is. Lucas 1982 it was bound to perish sooner or later!