The passenger side tail light does not illuminate causing a message center display of "Check Rear Lights".

History:
Had the "Check Rear Lights" message before and it was the brake light/cruise cancel switch on the steering column. I removed the switch, re-soldered the connections on the micro switches, and it resolved the issue.

Symptom:
The "Check Rear Lights" message only occurs when the headlights come on. With the headlights off, I do not get the message ... tail lights only come on with headlights.

Already done:
All fuses in the trunk good
Swapped out tail light relay
Swapped tail light bulb
Adjusted tail light contact in bulb holder
Added additional ground wire to both bulb holder assemblies

I'm at a loss for what to check next. Let me know what you think it could be, like I said, this message only occurs when the headlights come on.

Mark

 

Mark,
I'd treat the no tail lamp and bulb fail message as two separate issues, although I suspect that they're connected.

I'm a little confused about the taillights only come on when the headlamps are on. Does that mean that you can't just run on sidelamps?

Deal with the missing rear light first. You've done most of the obvious checks, now you need to do some tracing with a multimeter or a test lamp. Start at the bulb contact on the tail light assembly and work back through to the SLM. There's a thread here that may help:

https://www.jaguarforums.com/forum/xk8-xkr-x100-17/help-sorting-tail-light-wiring-160077/ and you can download the wiring diagrams from Gus' excellent site: JagRepair.com - Jaguar Repair Information Resource

HTH,
Mike

 

Mike, sorry for the late reply, this car is a daily driver during the summer and now that it is put to bed for the winter I can finally tear into it and diagnose the issue. I was hoping it was something simple last summer, but I had a feeling it might be the SLCM.

Please disregard the "tail lights only come on when the headlamps are on" statement. The tail lights function as they should (with marker lights and headlights on) but only the left side illuminates.

Note: Right Rear Tail Lights don't illuminate, but all other rear lights do illuminate (indicator, brake, reverse, fog).

Thanks for the link to the thread link about sorting the tail light wiring. I went through it and took my SLCM out to check for fried resistors, but everything looks good. However, it still feel like something is wrong with the SLCM because I took the following voltage readings today with the engine running.

Fuse #19 = 14.4 volts
Fuse #21 = 14.4 volts

Left Tail Light wire terminal (RU) = 14.4 volts
Right Tail Light wire terminal (RG) = 11.9 volts

I would have thought that having 11.9 volts at the right tail light connector would have illuminated the bulbs, but it does not. When I connect the right tail light terminal directly to the battery with alligator clips, the bulbs do illuminate.

Any suggestions?

Mark

 

Hi A2H,
Agree that 11.9 volts would light the lamps, so somethng doesn't quite add up.

Quick Q (forgive me) when you measured the low 11.9 voltage at the RH tail lamp, were the bulbs in place?

Mike

 

The 11.9 volts reading was taken at the connector in the trunk for all of the passenger side rear lights, not at the bulb terminals. 11.9 volts between Black and Red/Green wire for tail light. This is the voltage that the SLCM is supplying to the passenger tail light connector (before the bulbs).

Mark

 

So the bulbs weren't connected when you measured the 11.9 volts?

Bear with me...

 

Correct.

I just pulled a bulb and measured 11.9 volts in the bulb socket, but the bulb does not illuminate. Swapped driver and passenger bulbs and still nothing on passenger side, but driver side works.

Mark

 

OK. Now it makes sense.

The current drawn by the multimeter is tiny. I suspect that the feed resistor in the SLM has gone high-resistance.
It doesn't have to look burnt for this to happen.

Measure the voltage at the bulb connector with everything hooked back up.
If I'm correct, you will see zero or very close.

If you are handy with a soldering iron, or know a man who is, then it's a pretty easy, and best of all, cheap fix.

From memory, it's a 1 ohm 5 watt wirewound, and that sounds right for the twin-bulb tail lamp configuration that you have.

Do the above check and report back. In the meantime, I'll confirm the value for you.

HTH,
Mike

 

Mike, you are correct. I hooked everything back up and measured the voltage at the connectors. Driver side was 13.3 volts, passenger was 0 or close to it.

I will pull the SLCM again and await your reply with what to replace, thanks.

Mark

 

OK.
I imagine that you've already been there, done that but - for the sake of good order - do check the multi-connector and the wiring between it and the lamp cluster to make sure it's not just dirty contacts before you pull the SLM.

Here are the SLM resistors that feed the tail lamps:


R79, R92. Sadly I can't tell you which one feeds which side as I don't have a later SLM to reverse-engineer. Replace both as it certainly won't do any harm and the other might have been stressed and just waiting for you to button everything back up before it fails

Here's a link to the part, kindly posted by WhiteXKR:
AC05000001008JAC00 Vishay BC Components | Resistors | DigiKey

1 ohm 5 watt 5% tolerance. Princely sum of 78 cents each.

You will see that the resistors in the picture are mounted tight to the circuit board. I don't know how much room there is in the later SLM, but will be better if you can leave a gap underneath: up to half an inch if possible, but not so high that they're nudging the lid of the SLM. Idea is an air gap all round.

One caveat: replacing the resistors will cure the lamp out, but you might be left with a 'bulb fail rear' message. In Razorboy's case (previously linked thread) there was further damage to the SLCM sensing circuit.
Others have been just fine.

Please let us know how you fare.


Mike

 

Mark, you used blue wire for volt measure. This wire melts causing bulb failure message. Measure incoming volts to chassis ground. Your note about headlights raised my suspicion. The greater the current draw through a bad gnd = fails msg. Does reverse or rear fogs add to the issue ?

Search for brutal' s ( author) post on replacing ground wire rear lights. I just did mine. Good luck

 

Mike, thanks for the photo and link to the resistors. I ordered some yesterday and will let you know the results after I install them. BTW, yes I did check the multi-connector (and all connections) in the circuit and they were all clean.

John, I measured tail light voltage all bulb socket and multi-connector both with vehicle wiring and directly to chassis ground (same results). I installed my own lamp assembly ground wires last summer for each of the rear lamp assemblies too. All other lights (reverse, stop, indicator, and fog) work on both sides. Only the passenger tail lights don't work.

Mark

 

Success, thank you Mike.

Received the resistors yesterday and soldered them in this afternoon. Both tail lights work and no "Check Rear Lights" message any more.

Merry Christmas everyone.

 

LOL. Ironically enough my '05 just started the same thing. 'Check Tail Lights' and 'Cruise Control Cancelled'. All lights appear to work correctly, while the problem is intermittent. I'll visit the shop today and mention this fine forum.

Thanks muchly and a Happy New Year to all.

Jip

 

Jip, if your lights are working and you are getting both of those messages it probably isn't the resistors that I replaced.

I had the same problem last year with both of those error messages and it was the Brake Switch above your brake peddle. There are two micro switches in it (one for the brake lights and one to cancel the cruise control). I unsoldered the micro switch contacts and resoldered them and it solved the problem. Here is a guide to replacing the switch JagRepair.com - Jaguar Repair Information Resource

 

Typically, the culprit is the brake switch. It is actually a combination of 2 switches opposite one another (one normally open and the other normally closed). With time, one of the switches occasionally stops working, which can readily be detected by the control module (the switches should always be opposite one another, foot on or off the brake). This results in the message "Check rear bulbs, cruise control unavailable'. Feel free to search, there are lots of posts about this. The individual switches have been identified, so it is possible to repair the part (soldering required). A new part is also available, but is not entirely cheap, so shop around. Installing it is a bit of a bear because of the tight space, but is otherwise straightforward.

Best of luck, keep us posted.

 

Having never done the switch and bracket on a Jaguar before, I removed the switch from the bracket and replaced just the switch. I simply bent the bracket away from the pedal. replaced switch, depressed the pedal and bent the bracket back to engage the brake pedal. That was 2 months ago. Works fine.

 

Wow. Thanks guys. And here I thought the first solution was pinned down and a much easier repair surfaces. I'll print this out when my Mechanic buddy gets back after New Years Eve. I'm certainly not 'telling' Jeff what to do, but I figure a little information might eliminate some time on the clock, which =$.

Jip

 

I have had a similar issue in a Chevy. The multimeter read 12V but the light wouldn't come on. There were enough amps to light the multimeter but enough to light the bulb. Drove me nuts 'till i cleaned the ground. The light worked fine.
Now for the 2000 XK8 the right tail light plug (female) and male terminal it plugs in to are melted. I added an additional ground at the right light. Now I need to replace the female plug plastic. I can't seem to figure out how to pull the terminals out of the plastic housing to replace it. I thought I'd use all the old multicolored wires and replace the black(ground) female terminal on the end of the black ground wire.
How in the world do the wires come out of the plastic plug?????

Thanks