I have a 1994 xj6 when I turn on the running lights they do not come on most of the time. Every now and then they work fine, most of the time they do not come on. turn signal lights work 100% of the time both front amber lights and rear red turn signals work 100%. Brake lights work 100% when I apply the brake.
Its the running lights both amber front and side marker and both red rear and red rear side marker lights and tag lights work about 20% or less of the time. Any Idea what maybe causing this? I am wondering if it is the light switch it self the lights should work when I put the switch in the first position however they do not. The headlights work 100% of the time when I put the switch in position second position. Any thoughts on what the problem could be?

 

Firstly, WELCOME to the Jaguar world.

Secondly, your 1994 is what is known as an XJ40 series. Confused, we all were in the beginning.

I suggest a repost in the XJ40 area, where you will get the best advice. the cars in here are not equipped with the fancy electronics of that, and later, models.

We did not get that feature on the cars down here so I am of NO help, but it sounds like a relay is not doing what it is designed to do.

 

I don't know if the XK40 has glass fuses or spade fuses. But, if glass fuses, rotate them in their slots. If the lights work reliably, then clean the slots, ad a bit of dielectric grease to the contacts and replace with new fuses. On my 87 SIII the fuses are under the hood, driver side (U.S) about midway to the headlights on top of the inner fenderwell.