My headlamp relay failed on my 83 XJS and the replacement was pricey. I searched around and found a readily available, inexpensive replacement.

It is listed as a sunroof relay for a 2001 Cadillac Eldorado
and carries part number of BWD R3018. $24.49 at the local
auto parts store.

It dips the headlights as normal and also has the ability to
flash the high beams. There is a schematic on the side of
the relay.

I hooked it up as follows:

S - Grd
30 - Dip/flash from switch
56 - headlight power from switch
56a - high beams
56b - low beams

I am still running lights via the fuses, but intend to upgrade the fuse box shortly as well as adding high current relays to handle the headlamps
in order to manage the current of my H4/H1 lamps.

 

Good work!

Cheers
DD

 

Out of interest, does anyone know which bulb type my 1991 H reg 3.6 Auto XJS takes for its headlamps? Is it an H4 3 Pin, or a H7 2 Pin? Cheers, Darren