Turns signals work fine, hazards work fine, I did put LED bulbs in the rear turn signal sockets.

Oddity is the green indicator lamps in the dash flash once, then stop flashing while the exterior lights keep flashing fine.

Not sure how that works. Stop the turn signal (or hazard) and restart, same thing, single flash off the dash bulbs.

I did see a comment elsewhere (downloaded and printed web info the previous owner collected) that the wrong dash bulbs can cause this, but I am not sure how. it would seem that repeated power impulses to the bulbs should cause them to keep lighting up.

Anyone have any insight on this?

Doug

 

The wattage of the led bulbs isn't enough to activate the ststem that allows the warning light, it assumes there is a bulb out. You will have to fit a resister in the system somewhere or refit the bulbs it was designed for.

 

Or modify the dash direction indicator circuit to work with LED bulbs, i really like the enhanced brightness of the LEDs in back for safety. People are so used to in-your-face bright rear lights anymore, they don't notice dim incandescent bulbs

In the end, I will probably end up with XJ-S bodied Chevrolet so everything works...

Doug

 

Don't think so.
I have exactly the same problem which started 2 days ago. Also, which may / may not be related I am also having the yellow ABS lamp flashing in sync. With the Left turn indictator.

 

I have the same issue but mine is in the front. The dash indicator blinked once and now they don't at all yet all outside signals work. I swapped to a clear turn lens and used led switchback bulbs. This way I have white led driving lights and amber turns and it got rid of the large amber signal lens in the bumper. I agree with rgp there needs to be a resister in the turn line which is on my list. I have caught myself driving down the road with the blinker on a few times.

 

I had that happen to my 85 XJ6. Signal lights working on the outside, One flash on the inside, just like AZDoug. Since I knew that the signals were working, I started to troubleshoot on the inside of the car and found no issues. I mentioned in one of my posts that I used the floating ground technique to get my side lamps to flash with my OEM signal lamps. Thinking that the problem was associated with that I decided to remove the side lenses to remove the lamps. With the lenses off I had a helper turn the signal lights on and noticed that the bulbs were not as bright as they were when I first did them. Pushing on the bulb, they got brighter and my helper told me that the light inside was flashing when I pushed on the bulb. I removed the bulbs and cleaned the terminals and installed new bulbs. Doing that resolved the issue of the one flash inside the car.
Having stated the above, I would recommend that you clean and tighten the terminals so that the bulbs fit tightly. This goes for the two front and the two rear bulbs. YOU NEVE KNOW.
That is Lucas at work. Corrosion plays havoc on these old Jaguars. The rule of thumb is CLEAN;CLEAN;CLEAN and then CLEAN again. I have disconnected every connector on my car over the years and cleaned them. That never fails.
NB: I learnt a long time ago that if your car came with brass base bulbs, do not replace them with silver base bulbs even though they work. Brass conducts electricity better that other metals

 

I am trying to figure out what this occurs.

I do not see any electronic gizmo/circuit board that controls the dash indicator lights, they look to be just normal wired.

Only things i can think of that would cause this is those burned out bulb notification modules in the harness, or something regarding the flasher? I haven't looked into the flasher at all, got more important things to do, like figure out the brake lights once i get a chance.

Doug

 

Doug,

You could just try changing the flasher relay for one designed to work with the lower current draw of LEDs. I did this recently in my project to change sidelights, brakelights and indicators with LEDs. My criteria was to try and retain the bulb failure systems working correctly and also avoid fitting resistors which, imo, would otherwise partially defeat the purpose of trying to draw less current with LED bulbs.

You can get a revised LED flasher relay form Gil Keane at Quicksilver Automotive (bettercarlighting.co.uk)

Cheers

Paul

 

Mine has OEM bulbs, so your solution sounds like it might be a winner. I have noticed that the rear indicators are not v bright, which is consistent with your fault finding solution.
Thank you!!