'm restoring 1986 Jaguar XJ6 that's been garaged for the last 17 years and found the light switch (master, left side of dash) loose. I've been told its a loose screw, and that entire dash has to be removed to tighten. Is there a simpler solution?

 

Whoever told you that is wrong. The light switch is accessed from below the dash. Poke your head under there and you will find the bezel screws; loosen them, pull the bezel off and you will be able to tighten whatever is loose.

 

it is very easy to remove the headlights switch BUT make sure you disconnect the battery before putting any wrench to the switch bolts. You can easily fry the wiring harness because one of the bolts is almost touching the Brown Always Hot wire that connects to the switch.

The switch is mounted to the bezel and to the dash frame with two 8mm bolts.

remove the panel under the dash by removing the two plastic dash corner finishers first.

then there are a total of 4 screws holding the panel, two at the front and two on the side. Then the panel is freed.

once the panel is removed, use a mirror and a flashlight to look behind the headlights switch.

there is at least one Fiber optic cable connected at the back of the switch, Do not pull or bend this cable or you will have to replace it. It can be pulled out by grabbing the brass sleeve at the front end of the cable with needlenose pliers.

 

Here's an illustration of the set-up. As others have said, no need to remove the dash.

https://www.jaguarclassicparts.com/u...itch-5-3-litre

Cheers
DD

 

Wow! What quick and helpful responses. Thank you all...I shall return.

 

Same issue here!
This helped me much, thank you very much!