Well, this is an interesting problem. When I turn on the left turn indicator, both turn lamps (left and right) flash together, as if I have turned on the flashers. I noticed this when replacing the right brake light bulb. Also, is the rear side markers supposed to flash with the turn indicator; I know the front side markers flash, but never noticed the rear side markers flashing to indicate a turn.

The right turn signal lamps operate normally, but the right rear side lamp does not flash.

Any my ideas on my electrical gremlins? Thanks.

 

Make sure you have fitted the correct double element lamps with the correct off set for the pins.
It is easy to get the wrong lamps, but you will find these are hard to install in the holder.
The wrong ones when forced in will bridge across the contacts and cause strange effects on the lights, including the one you describe.

Mellow

 

Hello Mellow,

i swapped the suspect bulb bulb with the bulb from the opposite side and got the same behavior. Both turn indicators flashing when only the left turn indicator is on.

But I did notice the lamp is very dim on the left side compared with the right side. It’s almost like it’s not getting enough voltage. The bulb socket like looks fine, but the bulb seems a little loose in the socket and diexn’t Snap into place.

i also wonder if the bulb type is correct, as it has a single base for the contact and all the other bulbs in the tail light assembly have “two” contacts. See the photo. Can anyone confirm that the indicator bulbs only have a single contact in the base.

And the faulty lamb bulb has continuity and the filament is intact. So the fault must be in the wiring or the bulb socket.

Thanks for all help.



Do indicator lamps bulbs have a single “big” contact instead of two?

 

Make sure all the fuses are ok in the rear power distribution fuse box located in the boot/trunk next to the spare wheel.
Again a blown fuse in this fuse box can cause strange faults.

Mellow

 

I wrestled with my indicator light problem until it got dark and didn't make much progress toward a solution. All the fuses are good and I'll check the relays in the morning. I also need to doublecheck Fuse No. 44, as it's identified as controlling the "left-hand reverse light, direction indicator, and side marker.

But I did discover a couple of interesting things while poking around.

The bulb socket for the indicator light on the right side of the boot operates just fine and has around 12 volts of power when the signal is turned on. The bulb flashes bright and consistent. But the bulb socket on the left side of the boot, the problem child, has only around 10 volts of power inside the bulb socket. So that explains the dim illumination of the bulb and the weak signal flashing.

So I suspect my problem further down in the wiring or somewhere. I did manage to get the main harness pulled out of the plastic bulb assembly on the left side and didn't see any burns or arcing on the prongs or contacts. I could only locate one ground point around the tail light assembly and it clean and tight. But I know there is another ground point the area hiding from me.

And by the way, the power for the bulb socket comes from the metal side of the socket (where the pins on the base of the bulb slip into the slots) and not from the metal spring at the bottom of the socket. Or at least on my car. Apparently, the flat, thin-metal spring is in there to put pressure on base of the bulb and keep it tight in the socket after pins on the bulb are in the slots.

So I'll keep poking around and try to limit my left turns when out and about.

 

check the stop tail light that you replaced is a 12v 23wx5w not a 21wx5w . that will cause problems .
the 12v+ is constant on to all bulbs in the frame at once . the front and rear modules switch -ground to the individual bulb on command to illuminate .
there is one ground point in the RH boot/trunk for the RECM worth looking at also . truthfully my money is on 1 incorrect bulb .
not necessarily the indicator bulb.

 

As you have now discovered Jaguar use a switched earth system with a constant 12 v live feed. (Most cars use a constant earth and switched 12v.)

There are two 12v power feeds to the LH lamp unit. (Or there should be!)
The brown wire with the white stripe is for the indicator and reverse lamp. Also the towing relay and the side marker lamp in the bumper if you have one. This is powered via fuse F44 in the rear fuse box.
The brown wire with the green stripe is for the stop lamp, the two tail lamps and the fog lamp. This is powered from fuse F57 (10A) in the rear fuse box.
These need to be tested for 12v when unpluged from the lamp unit or you will get a back feed voltage.

As mentioned by Datsports make sure you have the correct bulbs. This was my first guess as well as his!

Mellow

 

If you want to trace the wireing yourself here is a link to the official jaguar S-Type electrical guide for your car:

http://www.jagrepair.com/images/Auto...cal-2005on.pdf

Mellow

 

Thanks Datsports and Mellow for your insight. I should have thought to check the specs on the indicator bulbs (right and left sides) when I had them both out of the module earlier. I will do that tonight and also Fuse 44. I assume the “23W/5W” is the specified ratings for my car. Actually, I have had problems before with the parts counter giving me the wrong bulb, especially with the pins offset on the base of the bulb. I didn’t think to also check the wattage. I hope the RECM is not damaged. In the meantime, will check the grounding.

 

See if this thread is of any help:

https://www.jaguarforums.com/forum/s...llights-53056/


Although the symptoms were not exactly like yours, basically a bulb was receiving less than full voltage and operating erratically. That part seems to match your description, especially the low voltage. In this case, the fault was a different fuse that was blown, which has me scratching my head. As the lyrics say:

 

The answer was right before my eyes, as I was overthinking the issue.

It turned out to be Fuse 44 for the “Left Hand Reverse Light Light, Indicator Light, Side Marker and Trailer Towing circuit.”

I had had not pulled it because the side marker was still working, although it blinked with the indicator light, which was very unusual and a clue I overlooked that the fuse was going bad. Never thought to check the reverse light, which would have been tricky when you’re by yourself late at night.

lLet me also add that my test light indicated the fuse was good, since it was passing a little voltage while failing or least enough to illuminate my test light.

My theory is that the metal connector inside the fuses had not burned all the way through and a slither of metal remaining allowed just enough voltage to give a faint glow to the indicator light. Another clue was when I swapped the bulb from the right side indicator to the left side and got the same reduced voltage on a “known” good bulb.

But pulling the fuse fuse for a visual inspection discovered the problem. So iI’ve learned a lesson that a fuse can be going bad while still halfway working.

Now i’ll pick a Saturday morning with a big mug of coffee and have a “fuse inspection” session. Maybe i’ll solve some more of my electrical problems, such as the driver’s footwell light, Climate Control and radio cutting in and out.

Thanks to Datsports, Mellow, and KR98664 for your assistance.

Fuse 44 in the luggage compartment fuse box for the direction indicator lamp with damage in the top of the loop, but was still allowing a very voltage to pass through.

 

You would have got a back feed through the lamps, that is why your test light indicated the fuse was good.
If you try your test light on the socket with the fuse removed you will get the same result.
You have to take the fuses out to test them properly on these cars.

Anyway I am glad it is sorted now. Well done.

Mellow