Looks like my right hand headlight main beam isn't functioning on my 1986 XJS. First thing I did was to check the fuses, and I replaced all of them since they were apparently original from 1986. New fuses, still no right main beam. I can turn the lights on, and get left main beam, and if I switch to high beams, all four will come on. I went ahead and got a new headlight for the right outer one, and stuck that in there and still same--no main beam, but high beams work.

Thinking it may be a headlight relay, but figured I'd post in here to see if there were any other thoughts. Also, poking around a bit, seems that Jagbits wants like 140 bucks for the relay. O.o Any cheaper sources or known good replacements?

 

Main beam = high beam

Dipped beam= low beam

SO, if I understand, your main/high beam circuit is OK but your RH low/dipped beam is not working.

The low beam voltage for both sides comes from the relay on a single wire (blue/red)which then splits to the RH fuse and the LH fuse. Since the left side is OK the relay isn't the problem. The problem is downstream of the relay.

The RH low beam might not be grounded. Or might have a connector problem. Or it isn't getting voltage from the fusebox. Or the RH low beam fuse isn't getting voltage due to a wiring fault between it and the relay

The grounds, as I recall, are under one of the bolts at the extreme end of the radiator mounting panel.

You can visually examine the connector at the headlight.

With a test light or meter you can check for voltage to and from the fuse and to the RH low beam.


Cheers
DD

 

Ah, yes, wasn't sure on what the "dipped" beam really mean--hadn't heard it phrased that way before.

Will check the grounds for the RH. The connector on the headlight seemed fine, but if the ground is clean and well connected, then it sounds like I need to make sure the fuse box wiring is good (since fuses are new now). If that's good, then what else is downstream of the relay before the light socket?

 

From the relay to the fuse and the fuse to the headlight is just wiring. No other components.

But there's almost certainly some connectors somewhere along the line as well as the connections under the fuse box. Might be a good time to check/clean/tighten as many of them as you can find....even after you fix the existing problem

Cheers
DD

 

We yanks generally use "high beam" and "low beam". Our Brit cousins generally use "Main beam" and "dipped beam". You used a bit of both in your first posting.


Cheers
DD

 

er....you did check the bulb works . . . . ?