I have a 2004 Jaguar S-type 3.0L automatic transmission, 45,000 miles. WITH THE HEADLIGHTS ON, when I turn-on the RIGHT turn signal the follow occurs: the LEFT turn signal light, the LEFT running lights, BOTH reverse lights, and the small rear RIGHT-hand light, all blink together dim. When I TURN-OFF THE HEADLIGHTS, everything goes back to normal with only the RIGHT turn signal blinking. Since both the blinkers and the headlights are operated from the hand-lever on the steering column, it would appear that this is where the problem resides. I checked all grounds in the trunk, cleaned all the bulb seats, installed new bulbs, and checked the connectors for the rear light assemblies. None of this resolved the problem. Is this probably a short or grounding problem in the hand-lever switch? If anyone has had this problem or has knowledge of what might be the actual problem, please advise. Thanks

 

Hi
Sound like you have a fuse gone on the rear light
theres 2 fuses to each rear light, bet you will find one has gone
cheers
Joe

 

I previously checked and all fuses are good, including the ones U indicated (F44, F48, F53 & F57). So fuses are not the problem. All lights work normal when the headlight is off. So fuses is not the solution. Thanks

 

Could be your light stalk malfunctioning on the steering column.

 

Is the term 'light stalk" the same as the light switch assembly? If so, i"ve removed this assembly but dont know how to test it. I've looked at the exterior electrical lighting drawings but cant make the electrical connection from the Light Switch, to the Instrument Cluster, to the Front or Rear Electronic Module (which is shown to actually feed the lights in the Headlight Unit. The problem appears to be a grounding issue, but I cant trace how this is happening by looking at the electrical lighting drawings. Since the problem only appears to happen when the front lights are turned on via the light switch, possibly this is the culprit, but i'd hope to have more evidence to avoid purchasing parts I dont need. Any advice?

 

Yes.

It can be a little confusing, as there is no direct electrical connection from the main light switch all the way out to the individual bulbs. There IS a more or less direct connection between the light switch and the instrument cluster, via five wires in parallel. The instrument cluster converts these analog inputs to a digital output, and sends this command off (via a data bus) to the respective control module to turn the individual bulbs on or off. It may sound complicated, but in a way it is much simpler than older vehicles. Rather than dozens and dozens of wires to individually control each circuit, the same work is done with far fewer wires. The only drawback is there's no old-fashioned tracing possible from start to finish.

Note all of the resistors inside the switch itself. Just that alone gets a little confusing. It's not like an old-fashioned switch, with battery power routed through the switch and then away to the bulbs. It's a bunch of resistors arranged around the 4 individual poles inside the switch assembly, with 5 wires connecting it to the instrument cluster. The instrument cluster reads these 5 wires and the resistance between all of them. As you select different functions, the resistance measured between certain wires will change. The instrument cluster interprets these input values and deduces you must have requested high beams, for example, and sends the corresponding output to respective control module.

This usually works very well, and cuts way down on the amount of wires needed. The wires can be much smaller, too, as they are carrying only a very small signal, not the relatively heavy current of the bulbs. This compactness is a big plus in the tight confines of a place like the steering column. The downside is any time some crud accumulates on the switch contacts, it can add resistance where none should be and cause erroneous outputs.

But what does this mean to you for troubleshooting? It can be very time-consuming to test each function of the switch, and do the math for how much resistance you should see between all combinations of wires. Not impossible, mind you, but still a lot of work. What's your time worth? Do you want to be absolutely, positively sure before opening your new wallet for a new switch? Are you willing to gamble on a used one from eBay? Only you can decide how much more additional troubleshooting you want to do before just trying something and seeing if it works.

 

Hi
Just out curiosity have you checked you have 12 volts on one side of each bulb on the rear light that doing it
I know you have checked the fuses, but seen this so many times when a fuse has gone, just wondered if you have 12 volts on all the bulb
theres a permanent 12v on one side of each bulb on these and rear module switches the earth to bring the bulb on
could be a bad connection on rear light or module
cheers

 

I've previously checked the connections on the REM. All rear lights and blinkers work properly when the headlights are off, so I think they are getting a strong 12 volts. When the HEADLIGHTS are on along with the RIGHT TURN SIGNAL (not the left), not only does the right turn signal operate/blink, but the reverse lights, trunk lights, and one left-hand brake/running light all blink dim together. Then if i turn-off the headlights, all the lights operate/blink correctly. I bought a used light switch/turn signal unit from the junkyard and did a replacement, but no change. Im not sure if it was any good though. So im taking another chance and ordering a used but hopefully better/working switch from online. Based on my interpretation of the electrical drawings (Exterior Lighting: Rear, Fig 08.3), the light/turn signal switch unit is hard-wired to the instrument cluster, then the cluster sends a network signal to the Rear Electronic Module (REM), then the REM sends an output to the respective lamp to light. Since everything works properly when the headlights are off, then I have to assume that "normal" signaling from the light/turn-signal switch unit, to the instrument cluster, to the REM, to the rear lights are all OK, just not when in the headlight on-position. So I rationalize to conclude that since the headlights are part of the turn-signal switch unit and appear to be causing the malfunction, then the light/turn-signal switch unit must be the culprit. Seems like the wire(s) for the headlight on-position on the switch causes a ground to all of the other switch wires which operate the reverse light, trunk light, running light, brake light, turn-signal light, etc.). Comments/Input/Feedback

 

Hmm, the plot thickens...

The erratic behavior of the trunk light is very unusual. I don't think a fault with the light switch would cause this. Headlights on or off, even if uncommanded, shouldn't affect the trunk lights.

I didn't realize you'd already tried another headlight switch. Even if the original was bad, it's hard to imagine a used replacement causing the exact same obscure problem.

Time to put on my orthopedic thinking cap...

Please see these two threads. Seemingly unrelated fuses were blown and caused strange issues with various lights:

https://www.jaguarforums.com/forum/s...ystery-219022/


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

 

hi
another thing worth checking, seen this before that also did something similar
check the stop/tail bulbs, they should be P21/4W but Ive seen people put in P21/5w
if the pins are exactly opposite there the wrong bulb and the contacts can short both terminals
the pins are not exactly opposite on the P21/4W, but the other wrong bulb P21/5W goes in quite easily
worth checking
cheers
Joe

 

I've seem both of the threads referenced above. None resolved my problem. And yes the License Plate Lamps blink when the lighting malfunction occurs. The "Exterior Lighting: Rear" drawings show an output from the Rear Electronic Module (REM) to the License Plate Lamps. The License Plate Lamp is not specifically addressed in the "Main Lighting Switch" detail drawing. I assume the signal for it initiates from the "Main Beam" and/or "Auto Lamp" signal.

I went outside at 8:45 pm tonight (Sunday) in the dark, Started the car and played with all the lights and turn-signals. Even though the instrument cluster read "LH Brake Lamp Failure", all the lights and turn-signals worked perfectly (which is crazy!!). In fact, I had a hard time simulating the problem. Then when I applied the brakes, the "LH Brake Lamp Failure" message actually disappeared, so no messages other than "door open". So now all the lights and turn-signals are working perfectly, then I turn-on the Hazards and the light/blinking problem starts back again. And now the instrument cluster is also reading "LH Brake Lamp Failure" and "Tail Lamp Failure". This is crazy! I've checked ALL the fuses in the luggage compartment fuse block, as well as cleaned the sockets and replaced ALL the rear lamps, still no resolution.

When I locked the car on Saturday evening, the light/blinking malfunction was still there. Now on Sunday, when I initially get in the car, everything works (NOW WHY IS THAT, MAKES NO SENSE!!). Not until I turn-on the Hazards do the lights start malfunctioning again. THIS IS CRAZY!! Seems like the best sure thing is to replace the Light/Turn-signal unit, Instrument Cluster and REM. But I'd really like to diagnose the issue. I've already installed a used Light/Turn-signal unit from a salvage yard (dont know if it was any good), and now I have another one on order from Online. I dont know of a way to actually check the Light/Turn-signal unit, Instrument cluster and the REM.

Comment/Input/Feedback?

 

Are these two lamp failure messages new? I think so, but want to be positive.

Just guessing, but I think you get these messages if the circuit resistance through each monitored bulb is out of a predetermined range. This could be a problem with the bulbs themselves, or the connecting wiring.

What brand of bulbs did you install? A name brand or something generic? Just wondering if you've got some bargain brand and the resistance is outside the range the car is expecting to see.

 

In effect it measures the ohms (resistance) / current flowing to figure if a lamp is defective so any weird power/ground path or somewhat failed lamp (filament part-broken etc or of course fitting just an LED) or a cross-connection can trigger the message(s).

None off those commonly occur but the cars are not getting any younger...

 

The two lamp failure messages are not new and have been displayed since the initial problem. The two messages display off and on. I dont think the issue is with the bulbs themselves since the lighting/blinking problem is exactly the same with both the old and new replacement bulbs. All of the bulbs work and light brightly when the headlights are off. The new replacement bulbs are Sylvania. As for the wiring, I've disconnected, wiggled, and inspected all the wiring at the two lighting lamp assemblies, as well as the REM (Rear Electronic Module). Thats about the limit that I've done involving wiring. Still no resolution.
ANY COMMENTS/INPUT/FEEDBACK??

I will try to place my vehicle info into my signature line.

Does this website allow the attachment of a video? If so, I have a video that shows rear lights mallfunctioning.

 

I removed both of the rear lamp assemblies and hooked them to a battery. I provided 'a touch of power to each of the 7 connector pins. 2 of the pins were ground and all the others served the lamps. All of the individual bulbs lit. The tail part of the tail/stop lamp and its auxilliary lamp lit together from a single pin. Power to one of the other pins allowed the stop part of the tail/stop lamp to light. An individual and separate pin served each of the other lamps (reverse, brake and fog). So it doesnt appear that there's anything wrong with the rear lamp assemblies.

 

Not trying to bust your butt, but that would have been helpful to mention at the beginning. This means the REM is not happy with the circuits through those bulbs. This is probably amp draw out of specs when illuminated, or resistance out of specs when off, or both. I'm still not sure how this factors into the problem, but it's another clue.

As far as the bulbs, Sylvania should be good. Incandescent, right? Not LED or something non-stock. LED bulbs can be notorious for triggering a lamp failure message, as their resistance and amp draw is far different than stock. It's possible some super-bright non-LED bulbs could also trigger the message. For now, I'd make sure you have bone stock bulbs installed, not something brighter than stock.

Are you positive you have the correct bulbs installed, as detailed previously? If a clerk looked them up at a parts store, or you did so yourself, your source document may have been wrong. Going back for another set of bulbs won't help if the book is still wrong. (I encountered this with a water pump for my '02 V6, where 5 out of 6 sources all listed an incorrect part number.) Not sure of the most accurate source, perhaps the owner's manual or some Jaguar vendors.

One last thing, please check the following fuses. Some you've already checked, but I think some will be new:

Rear Power Distribution Box (in trunk):

F44
F48
F53
F57

Primary Junction Box (in cabin, outboard of US passenger's feet):
F8
F9
F10
F11
F23
F25

In addition to making sure the fuse hasn't blown, check that each one fits snugly in the socket. I've done this by snipping an old fuse in half through the plastic, so it only has one prong. With a pair of needlenose pliers, you can individually check both sockets for each fuse. If either side is loose, you've got a problem that needs to be corrected.

 

You need to test that there is a constant live feed to the LH turn light when the fault is happening with everything plugged in.
This is pin 6 on the lamp conector the wire is brown with a white stripe.

I am sure you did this, and you probably already know, but the fuses must be tested when unplugged from the fuse box. Using a meter when the fuse is plugged in will give false readings.

I would also inspect the rear electronic module to make sure that it has not had any water get into it or its connector, this can happen if the trunk/boot, lamp cluster or fuel filler seal is poor.

Also has your car ever had a tow-bar fitted? If so they may have not used the jaguar item and connected into the rear light wires. Often when the physical tow bar is later removed they just leave the electrics, and this can cause problems later.
Also, other after-market fittings like reversing cameras can also give problems.
You may need to have a good look around in the trunk/boot for any obvious non original wiring.

The lighting stork/switch uses different internal resistances to give signals to the instrument cluster again these are all switched earths not live. The RH turn. LH turn main beam and headlamp flash all use the same earth feed to the switch.

One other thing to note, that agian you may probably already know is that all the switched feeds to the lights are all switched earths.
The live feeds (there are 6 in total for the rear lights) are constant not switched.

Mellow

 

I have seen weird behavior like this when somebody replaces a tail light bulb and uses the wrong bulb (one filament instead of two or the bulb isnt twisted in all the way causing shorts) so powering the light circuit shorts over to the brake light filament and illuminates that circuit also. so if anybody has been changing bulbs it might be a good idea to revisit those locations to see If there are any shorts across the dual filaments in the connector or the bulbs

 

Yes there is a constant live feed to the LH Turn. The Lamp Assembly board is always hot.
All applicable fuses have been tested good.
Just based on visual inspection, the REM doesnt appear to have gotten wet,but I cant confirm that. I replaced the connector that plugs into the REM but not chanage.
My car never had a tow bar or reverse camera. All the wiring appears to be original and intact, no obvious tampering.
Yes Im aware that all the feeds to the rear lights are switched earths. Thanks M-e-l-l-o for the input.

My problem started before i replaced any light bulbs, and all bulbs were working at the time. Once I installed all new bulbs, nuthing changed, problem was still there. I've previously cleaned and checked the installation of all of the bulbs. Thanks for your input Aarcuda.

I performed another test. I used a test light on the REM terminals while operating the RH and LH turn signal lights. Im not sure of this, but I thought I should probably get "TWO" separate oscillating ground signals (one for the RH turn signal and another for the LH turn signal) from two of the REM terminals However, only "ONE" of the terminals oscillated the ground when I operated the LH and RH turn signals. Does anyone know if this is how the REM should work, wouldnt appear to be so based on the 2005 Jaguar electrical drawings? No matter what I do, I cant get the REM terminals to produce ground correctly (based on using a test light) such that lights operate properly. The ground wiring feeding the rear lights arent being "switched" off and on correctly (by the REM) like they should. For example, if I turn on one of the turn signals, one of the REM ground terminals should switch off & on to make the light blink. As another, if I put the car in reverse, two of the REM terminals should activate ground to turn on both of the reverse lights. This has been my assessment but Im not positive and dont wanna spend $$$$ for a REM I dont need. Comments/Input/Feedback?

 

Maybe it is time to roll the dice with a replacement REM. Can’t say for sure, obviously, but we’ve wanted to rule out some other possibilities.

IIRC, other forum members have reported good results with used modules. eBay is a great source. I think the trick was to find a replacement with the exact same numbers on the label. Still working from potentially faulty memory, but then no programming was required. A quick check on eBay showed at least a half dozen under $100 for your year