XJ40 square headlights problems and dim/dip modules

[mccrackenj]

I thought I'd better start a new thread rather than continue one with a less than specific title.

As Groomi and Tr7v8 have advised on my other threads, my problem wih an inoperative 'sidelight' on the nearside of my 1990 Daimler probably won't simply be a faulty bulb but probably a faulty dim/dip module.

So that everyone's clear what I'm on about - the lights have 3 settings, i.e.

1 - sidelight, ie the sidelights in the bumper come on along with a low level brightness in the main headlights

2 - main headlights properly on

3 - operated by stalk - full beam on.

Symptoms

When I turn the control to position 1, both 'in bumper' sidelights come on and the offside headlight comes on as normal but the nearside flickers instantly, just once, like a bulb blowing, and then goes out.

In position 2 or 3 everything appears to be working correctly on both sides.


So, advice please - does this sound like the dim / dip module? Also - is there 1 module per side or does 1 module control both headlights?

Ta evermuch!

John

[Jaguarnut]

You have two modules, one either side of the Radiator at the top, easily visible. Just follow the wiring loom from the light unit to the box - about 10" of cable I think. Mine are literally 'black boxes', manufactured by "Hella", roughly 4" x 3" x1". My XJ40 is however a 4 headlight model, so the boxes may be different, but mounted at the same place. A Bulb failure module and dim-dip module in the case of late XJ40's are the same thing, all functions being catered for in each box You have one box for each headlight. The dim-dip mode is the control box supplying a lower voltage than 12v to the dip headlight filament - hence one bulb, two filaments (dip & full beam). switch to dipped headlights, control box supplies 12v. Simple.

You clearly have a defective unit on the side which is giving all the funny indications. You can try a new one (if available) source one from a breaker or get one froma company who refurbishes them. They are about. (See Jaguar World or JEC Club mags). Be careful however as there are differing versions, one for 2 headlight models, one for 4 headlight versions, both available with or without dim-dip mode!

[melhook]

The modules you are talking about, should all be Dim- Dip. Ie your dipped headlight comes on at reduced voltage. It is sometimes possible to take these apart and find the dry solder joint thats causing the problem. I have about a 75% fix rate on the modules, so if you or a friend is handy with a soldering iron and a magnifing glass you might be lucky !!

[mccrackenj]

I am looking at a pair of "front light relay modules" on Ebay, described as being for a 1992 on square headlight XJ40. Did these change in 1992? In other words is there no chance that these would fit my car, which is reg'd March 1990?


Thanks

[melhook]

From memory, although it' going back a while, the connectors may well be different. However you could phone your local Jag dealer and see if they can help. Maybe they could look up on their parts computer. ?
have a look at the jag site. www.jdht.com see if you can find your car, and part number, that way you can ask the e bay seller which one they are selling.

[Jaguarnut]

I think that there is a part number on the case - probably Hella as opposed to Jaguar, but I am not sure. If there is, you could contact the seller to confirm part numbers.

[mccrackenj]

Good idea - I'll have a look tomorrow afternoon or Saturday.

Cheers