The back up lights on my car aren't working. The bulbs are okay, but they don't come on when the car is put in reverse.

The original owner replaced the transmission with a GM transmission - the model I don't yet know. I did take the car to a reputable jag repair shop. The guy told me that the GM transmission doesn't have any switch or wiring to connect the lights up to.

I thought that when I got the car (I've had it for over 10 years now), that the lights worked. It did pass CA inspection then.

So, any ideas? Should they work? Or is there a way to make it work?

TIA

ken

 

The reverse detent on the shifter has a switch that activates the reverse lamps. It makes no diffrence what transmission you have.

 

The Ser III XJ6s were built two ways: a transmission mounted reverse lamp switch or a gearshift mounted reverse lamp switch.

The gear shift mounted type is #4 in this illustration. This was for all V12 Series IIIs and 'early' six cylinder cars. I've never known when the exact change point from 'early" to 'late' was.


Selector Gate and Lever-5.3 Litre-Automatic - Parts For Series III Saloon | Jaguar Heritage Parts UK

If you have this type of switch.....the gearshift mounted type....then it's simply a matter of normal circuit diagnostics: fuse, power to the switch, power out of the switch, lamps grounded, etc

If you car originally had the transmission mounted switch (I'm betting it did...but can't say for sure) then it surely went bye-bye when the GM trans was installed. If that's the case then retro-fitting a gearshift mounted switch might be the easiest choice

Cheers
DD

 

That must be the case. The mechanic said that there were wires (from the car), but no connector on the transmission.

Not sure how easy it would be to retro-fit. I asked the mechanic about "jerry-rigging" something, and his (first) reply was that they don't "jerry-rig" anything. Okay poor choice of words on my part. But he did not sound optimistic about hooking up a switch to the gear shift.

I guess the next question would be: are the lights needed/required? I've had this car for about 10 years now, and it was only last year that someone complained that my backup lights weren't working.

ken

 

I'll wager a week's pay that the mounting hole at the gearshift is sitting there empty so installing the switch would be easy. Routing the wires might take a little effort....but certainly not a major project. It's "doable".


If you've gone this long without 'em, well......


Cheers
DD

 

There are a couple of ways.


1. Change the shift tower for one from an XJS. It has a switch for the back up lamps. I did that. Added "advantage". The detents match the GM positions just a tad better.
Access to "L' more likely to be possible.


2. Adapt a backup switch to the XJ6 tower. In my tower, no screw in opening was present. But, a large washer and a suitable nut made it feasible. Or, merely, weld in a suitable bung.


3. Further fetched: Down under. By the lever that shifts the transmission. Create a mount for a micro switch that closes when the lever is in the reverse position. They might blink as other gear positions are selected!!


4. Add a manual toggle or button ala LnrB's solution.


5. Forget about it.


Yeah, I understand the shop's position on "jury rigging". if it goes bonkers, who gets the blame...


Carl

 

LOKAR makes a unit that bolts onto the transmission $40 or so Summit Racing sells them among others.