I came across post that showed how to replace the Hella headlight relay. I wish I had come across it sooner
as my headlights have failed. I am sure that the instructions are simple enough for most everyone on this
forum, but I think that I am on the left hand side of the bell-shaped curve when it comes to electronics.

So, my query is whether anyone has any diagrams or schematics that identifies the wiring
by color code or perhaps photos of the lighting switches and relays and how to wire them.
And, before anyone suggests that I am asking to have the information spoon fed to me; yes,
I know, sadly, that is exactly what I need.

Thanking you in advance for your patience...

James

 

Are you aware that 95% of headlamp issues on these cars are traced to the fuses in the engine compartment fuse box? And that simply removing the fuses, tightening and cleaning the cradles will cure the problem? You do not explain what you mean by the headlamps having failed, but on the Series III cars the first course of action is to check the fuses for ANY electrical issue.
But your profile indicates that your car is an S-Type….and the above does not apply…or are you in fact asking about an answer regarding a Series III XJ?

 

In the "stickies" at the top of the Forum you will find a list of "how to" files. Item 5 is the S57 wiring diagrams for your car. These diagrams are most excellent and break down the wiring by function , so when you are looking at the headlight wiring it wont be amongst a maze of other stuff. The also include colour codes and pin numbers as applicable.

 

Gregory:

Thanks for the reply. Yes, I am in fact talking about a Series III XJ6. It's a 1983 with a ZZ4 Small Block. I have already
cleaned and tightened the fuse cradle. I wish it were that easy to fix the failure. And, I don't know what else to call it, as they
were working one day, but not the next. Frustrating.

 

there is a small fusebox with 5 fuses on the driver's side of the engine compartment, near the washer bottle for the wipers. This is the fusebox Gregory is mentioning.
The first 4 fuses are one for each headlight. The fifth fuse was / is for the auxiliary electric fan under the front bumper, if you still have it.

roll each fuse in place with the headlights switch ON to see if those fuses are the issue. You might be surprised.

 

Thank, you, I will certainly give it another try.

 

So, yeah; the fuze box is shot. And, I'm not so certain that the relay is working either.

Going to try and install Steve's relay upgrade.

 

More information about the fuse box, please. What is its condition? All fuses faulty …or…?

 

Might take a peek here

https://www.jag-lovers.org/xjlovers/xjfaq/headlamp.htm

Cheers
DD

 

Jiggle the wiring that leads from the fuse box and relay with the light switch on. Your headlamps will suddenly come on. Then you can repair the wiring or connections in that area underneath the coolant tank

 

If you want to do something methodical that will rule in/rule out parts of the system , try this:

Pull the blue/red wire off the headlight relay. Apply 12V to that wire. This should light the low beams.

Pull the blue/white wire off the headlight relay. Apply 12V to that wire. This should light the high beams.

If no headlights your problem is toward the fuse box and headlights. If you see headlights your problem is upstream toward the relay, its 12V supply and the switch.