I've been experiencing intermittent problems with my brake and tail lights on my '03 S-type, 4.2. Sometimes they'll function correctly for days and then I'll start up the car to run an errand and they'll start malfunctioning again.

Here are all the things I've tried over the past 2 months:
1) Replaced problem bulbs....three times. None of them appeared to be burned out.
2) Replaced ALL bulbs. None of them appeared to be burned out.
3) Installed Jaguar approved bulbs purchased from Ebay.
4) Checked fuses.....both were good
5) Checked to make sure bulbs were snug and installed correctly
6) Checked for water in trunk....trunk was dry.
7) Checked for moisture around tail lamp seals.....also dry.

Not sure if any of this is connected, but here are some other things that don't operate correctly on my car.
* driver's seat heater doesn't work
* key fob operates sporadically; must be next to the vehicle to work
* driver's seatbelt clasp (female end) jams and difficult to use
* ignition barrel has fallen back into the dash but still usable

It really is a nice car and I still get lots of looks of approval. I love my Jag and have not intention of getting rid of it, but I would like to find a solution to the sporadic tail light problem.

Can anyone help? It would be much appreciated. Thanks!

Bill

What "intermittent problems"?

BTW, fix the ignition as you're looking for grief as it is.

Intermittent problems = sometimes the brake and tail lights don't work

Thanks for the info on the ignition barrel.

I'd be willing to bet large sums of your money on a bad ground connection(s) for the tail light assemblies. I don't have the schematics handy (that would involve getting up from my easy chair by the fire and booting up my ancient PC in the chilly spare room) but there is probably a common ground somewhere. If each side has a separate ground, they may have still been exposed to the same conditions, such as road salt, water in the trunk, etc. Perhaps somebody with more experience can weigh in.

I'd also suggest checking the bulb sockets for corrosion and looseness. If the wrong bulbs had been installed at some time, that might have bent the contacts away, resulting in a marginal connection.

So.....could someone tell me where the ground connection for the tail light assemblies is found?

Are the lights malfunctioning on one side or both?

The seat heater check the fuse.
Key fob open it up and clean the contacts under the keypad
Seatbelt clasp a little WD40 or replace it.
Pull the shroud and refasten.

The brake and tail lights are malfunctioning on the left side....occasionally. And sometimes the rear turn signal on the right side malfunctions.

I would like to check the ground connection for the tail light assembly if someone could tell me where it's located.

See electrical guide - free download in JTIS - and be aware like many (most?) modern cars it's switched ground so you're maybe looking in the wrong place.

Is it both sides and the middle brake light as well? What about fog light?
As JagV8 said you should have constant 12 V feed. Check the brown-green wires in the assembly first.

You have to understand that that the rear(and front) lamps do not have individual ground points as in older vehicles.All the lamps have switched grounds---ie the circuit is activated by switching the ground to the lamp(as per JagV8 above).

The rear lamps on your car are controlled by the rear electronic control unit in the trunk,the ground wires for the control unit are grounded at a single connector on the RHS of the trunk.You have to remove the passenger side trunk trim panel to get at the connector.

If you need a copy of the wiring diagram for your S-Type send me your email in a PM and I will send you a PDF.

This is a link to the oneline for your car.

Link http://www.jagrepair.com/images/Auto...x2052003en.pdf

Oops, my bad. Sorry for steering you down the wrong (actually nonexistent) path.

My issue with the brakelights / taillights has been SOLVED. It was the RECM. My mechanic was able to get a used one for $150 and re-programmed it for my car. All is well....finally!

Where's the fuse box for the brake lights on a 2004 s type

The handbook says and if you don't have it then it's a free download as the stickies show

Fuller info in link Gus posted.

+1, with nice illustrations to boot.

dear puzzle solvers, continuing this thread... but what if I swapped out the Electronic body control and didn't solve the problem? I dropped 2 gallons of water in the trunk and towel + air dried most of it right away. Not sure if it got water to the 2 unknown programmable units (rear parking?) in the spare tire area. I also disconnected the front 2 fog lights and tapped them into after market daylight LEDs. Front highbeam and side markers, all after market bulbs. Tail also had aftermarket reverse and turning bulbs. Rear trunk interior light also tapped with low voltage decorative small led and everything worked fine before. One day i figured... when I use the turning signal to the right with the headlight on, it triggers the Right rear side tail turning malfunction yellow warning. Without the headlight on it doesnt trigger warning but problem is the same. **when i use the rear turning signal, the right tail turning lights up but dimmed, also the right reverse and left turning, left reverse also lights up all dimmed. When use reverse, the right reverse doesnt light up but left reverse lights up brighter than usual. When i use left turning the left tail turning lights up brighter and right tail doesnt so its somewhat normal. Tail fogs, brake lights work fine. Not sure my gear shift choking problem is related, sometimes shifting is very rough and shift too fast to high gears and triggers fault. not sure what to do with that either. Well, I'm scratching my head cuz i replaced the rear ECM (rear right trunk trim area behind the 2 other units) and swapped tail bulbs back to original but problem is the same. I plan to replace the right tail bulb circuit board. What should i do next? reprogram something? i thought the ECM is plug and play from another 03 S type, replace the left circuit board instead if it's the master control? how to check grounds wires?? please shad some light to this problem!

03 S type R

Not plug and play. Will go into anti-theft. Just disconnect all the odd stuff and will probably work.

Transmission Results: Transmission choke and rough accelerate and decelerate, random gears.... dealer said 3 qts low on transmission oil. Topped off, and never happened again.

Rear lights problem results: swapped the rear elec control module and the light assembly unit with the correct light bulbs, checked fuses, no luck. Took to dealer, he said bad wires underneath the fuse F44 (stop lights, plates, side markers...etc) and redirected the power with a new wire. Who would've thought to check the wires UNDERNEATH the fuses? now the sidemarkers and plate lights dont come on though everything else was fixed. Going to see what they have to say.

Both at $195 per complain + bulbs and trans oil. ouch.

I think you were charged a fair price. Especially if it was a Jaguar dealer. And they did find and fix both your problems.

You really need to find out why your transmission was 3 quarts low. Do you know about the leaking sleeve?

Have you checked the transmission pan for fluid? Normally people think it's the pan leaking because of where the sleeve is located.

At this late date and with running the tranny low on fluid I would immediately swap the filter/pan and change the fluid. The ZF is a good tranny but operating it low on fluid is sure to cause damage.

As was posted before the REM has to be programmed to work right and can't just be swapped. Did the dealer program your used one?
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