Trunk light failure 1998 xj8 base
#1
Trunk light failure 1998 xj8 base
I found that(with trunk lid open) that the lights work if I add a ground.
So I traced the ground wire harness only to find an inline part,(ford 91 ag 10374 / 89 7182 000) Two wires go into it.When I unplugged the part and added a ground to the inbound wire the lights worked....
What would that part might be?
So I traced the ground wire harness only to find an inline part,(ford 91 ag 10374 / 89 7182 000) Two wires go into it.When I unplugged the part and added a ground to the inbound wire the lights worked....
What would that part might be?
Last edited by GGG; 10-24-2014 at 06:33 PM. Reason: see post #2
#3
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jagslinger (10-24-2014)
#5
YES - it's my XK 4.2 Coupe. I've also had two XK8's in between since I sold my X308.
The X308 luggage compartment lid trim panel is fitted with two lamps which operate automatically whenever the lid is opened.
(click on the image to enlarge it)
The switch is incorporated within the latch mechanism (the black arrow is the harness to the BPM - Body Processor Module). The BPM provides an enable signal for the glovebox, vanity mirror, luggage compartment lid and map lamps. Actuation of the relevant switch provides an earth (ground) path to the lamp.
As you can get the lamps to operate by grounding, it's likely the microswitch (item 18) in the lock mechanism is the issue.
Unusual for Jaguar, it's available separately!
Graham
The X308 luggage compartment lid trim panel is fitted with two lamps which operate automatically whenever the lid is opened.
(click on the image to enlarge it)
The switch is incorporated within the latch mechanism (the black arrow is the harness to the BPM - Body Processor Module). The BPM provides an enable signal for the glovebox, vanity mirror, luggage compartment lid and map lamps. Actuation of the relevant switch provides an earth (ground) path to the lamp.
As you can get the lamps to operate by grounding, it's likely the microswitch (item 18) in the lock mechanism is the issue.
Unusual for Jaguar, it's available separately!
Graham
Last edited by GGG; 10-25-2014 at 04:14 AM.
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jagslinger (10-25-2014)
#6
Are'nt you the most.....Ha I was just telling the miss that we'll get her into a xk coupe as well as my self, not to far down the Jag adventure.
Rite now I'v got the xj8 to bring up to snuff,And enjoy.So thanks agin .
I'm not sure, but it was you or plum's info thread that resolved my last two problem's, but it did the trick......broken wire at the trunk lid hinge took care of the
license plate lights,And a corroded light socket was the brake light failure.
I'm looking for some electrical schematics, or manual that would have it .
AGIN THANKS....................Jagslinger XJ8 1998
Rite now I'v got the xj8 to bring up to snuff,And enjoy.So thanks agin .
I'm not sure, but it was you or plum's info thread that resolved my last two problem's, but it did the trick......broken wire at the trunk lid hinge took care of the
license plate lights,And a corroded light socket was the brake light failure.
I'm looking for some electrical schematics, or manual that would have it .
AGIN THANKS....................Jagslinger XJ8 1998
#8
#10
I found that(with trunk lid open) that the lights work if I add a ground.
So I traced the ground wire harness only to find an inline part,(ford 91 ag 10374 / 89 7182 000) Two wires go into it.When I unplugged the part and added a ground to the inbound wire the lights worked....
What would that part might be?
So I traced the ground wire harness only to find an inline part,(ford 91 ag 10374 / 89 7182 000) Two wires go into it.When I unplugged the part and added a ground to the inbound wire the lights worked....
What would that part might be?
I just replaced that particular part on my '99 XK8. It's a one-way diode that prevents feedback that might energize the lights even with the trunk closed. It also acts as some sort of temp sensor/ fuse according to other descriptions I ran across while searching for it, but it is most definitely a one-way diode.
Go to your local Ford dealer or perhaps Rock Auto online and order part # E9RY-10374-A. cost is about $19-20 new.
#11
I found that(with trunk lid open) that the lights work if I add a ground.
So I traced the ground wire harness only to find an inline part,(ford 91 ag 10374 / 89 7182 000) Two wires go into it.When I unplugged the part and added a ground to the inbound wire the lights worked....
What would that part might be?
So I traced the ground wire harness only to find an inline part,(ford 91 ag 10374 / 89 7182 000) Two wires go into it.When I unplugged the part and added a ground to the inbound wire the lights worked....
What would that part might be?
An additional thought. You can check the micro-switch at the actual trunk latch itself by using a multi-meter to check for continuity. Follow the leads coming from the switch (a little black box affixed to the latch down to it's disconnect (about 12-18"). Set the multi-meter to the symbol that gives you a tone when you touch it's probes together and then stick one of the probes into each of the wires coming from the switch.
With the trunk lid open you should get a solid tone that designates that current is flowing through one wire across the switch and down the other leg. If you get no tone then the switch is bad. Available on eBay and elsewhere as #LNC6242AB. Possibly attached to the latch itself for about $30 to $40.
The switch is housed in that little black box which will break if you try to pry it off so gently use a fine point screw driver or pick to release the small locking clip's at each corner and remove the switch and wire. That way you can do the reverse to reinstall a good switch if it turns out yours is bad.
I had to replace both on my '99 XK8
#12
Hi I am having trouble with the boot interior lights and the microswitch , first I had no lights when I opened the trunk, so I removed microswitch and made sure it was working then back together again, my problem then was lights on when boot closed and locking only possible with the key in keyhole, boot open message on dash and no central locking from key fob....basically now stuck in the opposite way ... My question is do I replace microswitch only or entire locking mechanism with microswitch pre attached? Which is easier solution because I seemed t break the plastic casing of the switch a lit? And is there any coding of keys fobs involved ? , phew complicated!!!
#13
trevor24 - go back and read the previous posts to this thread and run some continuity tests on the circuit from its power feed connector in the trunk all the way to the micro-switch. A multi-meter would be good by a test light could work almost as well.
Those micro-switches are pretty fragile and in taking it apart you may have damaged it. A test light will tell you easily enough. Also don't forget the inline one-way diode we talked about. That prevents almost exactly the feedback power you're experiencing that turns the lights on with the trunk close.
As for the key fob not working I'm not sure I understand. Are you saying that you can't lock or unlock the entire car with it or just the trunk? If just the trunk that wasn't lockable with the fob anyway as just closing the lid locked it. The fob could only activate the unlock function.
Does the dash mounted switch still unlock the trunk? If it and the key fob no longer unlock the trunk I'd have to think that the circuit controlling the micro-switch or the switch itself is bad and would need to be replaced. With the trunk open can you hear the electric motor that unlocks the trunk operating when you push the unlock on the fob? Without any way of knowing (easily) just what year and model Jag you have I can only go by my '99 XK8 as far as where that motor is located. In my car it's on the passenger side of the trunk's inner panel behind the trunk liner in a straight line from the latch so it can activate a simple pull action on a rod that pulls the trunk latch open.
I highly suspect the one-way diode may have been the initial cause of you problem as it also has some sort of temperature sensing properties that are designed to shut off the trunk lights in case of a failure to turn off that would cause a battery to go dead. Why any of that would also cause problems with the key fob is beyond me.
Those micro-switches are pretty fragile and in taking it apart you may have damaged it. A test light will tell you easily enough. Also don't forget the inline one-way diode we talked about. That prevents almost exactly the feedback power you're experiencing that turns the lights on with the trunk close.
As for the key fob not working I'm not sure I understand. Are you saying that you can't lock or unlock the entire car with it or just the trunk? If just the trunk that wasn't lockable with the fob anyway as just closing the lid locked it. The fob could only activate the unlock function.
Does the dash mounted switch still unlock the trunk? If it and the key fob no longer unlock the trunk I'd have to think that the circuit controlling the micro-switch or the switch itself is bad and would need to be replaced. With the trunk open can you hear the electric motor that unlocks the trunk operating when you push the unlock on the fob? Without any way of knowing (easily) just what year and model Jag you have I can only go by my '99 XK8 as far as where that motor is located. In my car it's on the passenger side of the trunk's inner panel behind the trunk liner in a straight line from the latch so it can activate a simple pull action on a rod that pulls the trunk latch open.
I highly suspect the one-way diode may have been the initial cause of you problem as it also has some sort of temperature sensing properties that are designed to shut off the trunk lights in case of a failure to turn off that would cause a battery to go dead. Why any of that would also cause problems with the key fob is beyond me.
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trevor24 (03-24-2016)
#15
#16
I think my lights also turn off after a while, safety measure to prevent draining the battery.
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trevor24 (03-29-2016)
#18
Did you change the switch already?
Mine did the same.
I DID measure continuity with a multi meter, but the switch only carried a load (lights on) from time to time, and almost always with a delay.
Replacing the switch solved all problems.
Mine did the same.
I DID measure continuity with a multi meter, but the switch only carried a load (lights on) from time to time, and almost always with a delay.
Replacing the switch solved all problems.
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deancantrell (03-29-2016)
#19
Yes a replacement latch with switch attached , not brand new though. I haven't taken any reading with a multimeter I might try that but I'm a novice so things go slowly! I was hoping a different switch would sort things out but it is basically doing the exact same , which makes me think perhaps a different problem,