The instrument panel backlight does not work. When I turn on any of the headlight modes. My dashboard goes out. I turned off the dimmer, everything is the same. The battery is connected normally, 12.7 volts, when the engine is running 13.7. On the board when the headlights are off 11.7 volts. When I turn on the headlights 2.5 volts. Please help what could this be. Fuses under the hood are all ok, and in the trunk. What could this be due to? It all happened spontaneously, while driving in the evening. I turned off the car and went to the store. When I came back, the backlight didn't work. Before that, I had only disassembled the rear speaker by the window. I took it off because it broke.

 

Look for a loose wire (broken solder joint) in the multi-purpose switch. Will need to remove the steering wheel and cover to the underside of the steering post and remove the switch and examine. You will need to a wiring diagram. What is your car?

 

There was a TSB for 1998 cars....
http://www.jagrepair.com/images/TSB/XJ/413-03.pdf

Or if all the bulbs failed here is a great guide to replacing them (Not written by me, just reposting)

 

I have jaguar xj8 sovereign 2002. Check the light switch, take it apart and check the condition of it inside? Yes, a wiring diagram would be nice. Due to the region, I can't find much information about this car.

 

http://www.jagrepair.com/images/TSB/XJ/413-03.pdf. I checked all the bulbs that are easily accessible from the back of the speedometer. 2 of them were burned out. But I replaced them. It did not help. The new bulbs also go out when the car headlights are turned on.

 

Jhartz was talking about the wires underneath the headlight switch. Remove the steering column covers and look underneath that switch. The wires are exposed and lightly soldered into place. They break off from movement. Remove switch and resolder into place.

 

[QUOTE=Addicted2boost;2849622]
Got it, thanks. I'll try in a few days and answer if it helped.