license plate light stays on

[G46]

Hi fellow members.

im having this trouble since day 1 i got the car, its a V8 730i 92 build.

the license plate, dash lights stays on eventhough the key is off and telling me "lights on?" warning.

ive ran through almost all keywords on different forum, ive checked the wiring loom going from the trunk to the body its all good.
ive taken out the light switch, see if it fixes it, but no, the license plate stays on. the switch is fine, the dim/parking light works as it should
ive taken out fuse #5, it should cut off the license plate light, but it doesnt. (weird)
ive read on e30 forum, if aftermarket headunit was installed, there should be gray/red wire and disconnect it, and ive checked mine just in case, no i dont have gray/red wire connected to my HU.
i believe nothing wrong with my LKM or mustard relay as i have no intermittent warning or light problem.

i traced the wiring from the trunk loom, going into the rear seat, and further more going to the left side of the car. and when it goes from the rear seat to the front seat, i cant take further action due to the car mat is freaking thick and heavy, plus the passenger front seat is electronic, i have no idea how to remove the electronic seat. cant seem to trace furthermore where the wire goes.

as i checked the wiring diagram, theres K25 relay under the LH dash. i think its energized when key is out, i wonder if you guys have a picture of the location, i cant locate it, even the component location chart did not show where the relay is.

currently i have disconnect the battery cable so that it wont drain the battery overtime.

any other ideas on how i can troubleshoot this issue.?

[e30luv318i]

Pull the light module and see if the light goes out, it’s located in the engine bay fuse box. It sounds like the light module is defective

[CroughtonE32]

In case you don't know where it is, it's the one that says LKM. Pull it out and plug it back in.

[G46]

the light did go out if i pull the LKM, every light on the car. how was this LKM suppose to do with the license plate light? i mean by how its suppose to let the contact stays on? and i saw 4 relays on the lkm, i believe it was only for front low and highs also respective left and right fogs.

[e30luv318i]

The lkm controls all your light functions think of the lkm as having various relays inside, when the switch is flipped a signal is given to the lkm to turn on various lights. Water damage, heat, vibration can all cause that module to fail. It has to do with your license lights because that and the CCM monitors and works your lights. I’m thinking it’s one of the 2 because there is an independent check of your license lights and running lights. If you think how would you license lights be on with out your parking lights ? There is no was to turn on lic lights with out parking lights... but you ccm and lcm individually work/monitor the 2 separately

[e30luv318i]

One last alternative I can think of is the wiring is broken in the trunk hindge and maybe making contact but that doesn’t explain the interior dash lights being on. I’m not sure of the inner workings of the lkm if it powers the dash lights ? normally that’s the light switch with grey/red you mentioned

[G46]

i did check the wiring loom on the trunk hinge, all seems ok, and theres 5 cable, i inspect and wiggle every inch of them, makes no difference, trunk compartment light goes on and off with the trunk switch pressed or depressed.

[E32FAN]

Hi fellow members.

the license plate, dash lights stays on eventhough the key is off and telling me "lights on?" warning.

as i checked the wiring diagram, theres K25 relay under the LH dash. i think its energized when key is out, i wonder if you guys have a picture of the location, i cant locate it, even the component location chart did not show where the relay is.

In the North American ETM, Page 6320-00 shows that K25 is for Canada (for our Daytime Running Lights requirement). Possibly you cannot find it because your car is not the Canada version. My cars are the Canada version.

For the USA version, there is no K25, and X12 pin 14 is fed from the S8 light switch X503 pin 1, Grey/Blk wire. If you pull F5 then the license plate lamps E43 and E44 go dark, yes?

Possibly your S8 light switch is defective - I have seen this happen.

[G46]

In the North American ETM, Page 6320-00 shows that K25 is for Canada (for our Daytime Running Lights requirement). Possibly you cannot find it because your car is not the Canada version. My cars are the Canada version.

For the USA version, there is no K25, and X12 pin 14 is fed from the S8 light switch X503 pin 1, Grey/Blk wire. If you pull F5 then the license plate lamps E43 and E44 go dark, yes?

Possibly your S8 light switch is defective - I have seen this happen.

Sir, if i pull out f5, it wont go out, if i remove light switch harness "disconnect it from switch" i wont go out either, the only time it would go out is if i pull out LKM, according to the drawing, LKM is the ladt one before license plate bulb

[E32FAN]

Sir, if i pull out f5, it wont go out, if i remove light switch harness "disconnect it from switch" i wont go out either, the only time it would go out is if i pull out LKM, according to the drawing, LKM is the last one before license plate bulb

Please see page 6320-00 and 01.

Current is designed to flow in X12 pin 14 and out X12 pins 31 and 39 to the license plate lamps.

Your LKM seems to have an internal short that sources current to pins 31 and 39 from some different path. Can you try a different LKM?

If you open your LKM you can trace these thick copper traces and possibly see the source of the short circuit. Perhaps a modification has been made, that could be removed? X12 connector pins are shown on page 8500-00

[G46]

currently i have no access to other LKM, but still waiting for my friend/local parts source to check one for me.

i did open up the LKM, no modification made but i can see one ruptured capacitor. however i can get an initial resistance and going to OL on my multimeter upon measuring the capacitor that has burnt mark may possible from ruptured.

IMG20180905085125.jpg

[shogun]

just for info, here I posted all the details, LKM and CCM pinout http://www.bimmerboard.com/forums/posts/1175396/

i have no idea how to remove the electronic seat

see my website for detailed instructions, or here http://www.bimmerboard.com/forums/posts/62868

[E32FAN]

Please see page 6320-00 and 01.

Current is designed to flow in X12 pin 14 and out X12 pins 31 and 39 to the license plate lamps.

Your LKM seems to have an internal short that sources current to pins 31 and 39 from some different path. Can you try a different LKM?

If you open your LKM you can trace these thick copper traces and possibly see the source of the short circuit. Perhaps a modification has been made, that could be removed? X12 connector pins are shown on page 8500-00

Of course the short could be before the LKM!

If you remove LKM and F5 and then measure X12 pin 14, is there 12V present? If yes, then the "short" is somewhere else, feeding the GR/SW wire. You can pull fuses until you find the source.

Page 6300-02 shows that the GR/SW wire feeds many lamps - including the E20 underhood light!

[G46]

just for info, here I posted all the details, LKM and CCM pinout http://www.bimmerboard.com/forums/posts/1175396/


see my website for detailed instructions, or here http://www.bimmerboard.com/forums/posts/62868

Shogun, would installing LKM-B works if currently i have LKM-L on my car?

and i can remove the rear seat, its the front passenger (left) seat i have no idea on how to remove it. my car is RHD btw.

[G46]

Of course the short could be before the LKM!

If you remove LKM and F5 and then measure X12 pin 14, is there 12V present? If yes, then the "short" is somewhere else, feeding the GR/SW wire. You can pull fuses until you find the source.

Page 6300-02 shows that the GR/SW wire feeds many lamps - including the E20 underhood light!

Thank you. i will start pulling fuses, need to backtrace wires then.

[shogun]

Shogun, would installing LKM-B works if currently i have LKM-L on my car? and i can remove the rear seat, its the front passenger (left) seat i have no idea on how to remove it. my car is RHD btw.

Just try it, should work also, the main difference between LKM- L and B is, that L checks the bulbs in cold and warm condition while the LKM-B only checks the bulbs in warm condition = when the lights are on.
Front seat removal is partly shown here http://bmwe32.masscom.net/sean750/Se...atSwapping.htm

Front seats have two bolts at the back and they are hooked in at the front.
You will need to remove these two bolt and also disconnect the seat belt ( 1 bolt at the side of each seat) and the tensioner cable under the seat. If you have heated or electric seats you will also need to unplug them underneath.
Once all are undone tilt the seat forward from the top to unhook it from the front. You might have to tilt forward first then pull it back towards you from lower down the seat back

Here with pics: Getting the seat out is straight forward: pop the headrest out, slide the seat forward, remove the two Torx bolts Photo-1 & Photo-1a in the rear & tilt the seat forward to disengage the front hooks Photo-1b. A 7/16 or 11 mm 12-point socket fits the Torx heads if you don't have a Torx "E14" socket. Remove the seatbelt bolt (also Torx E14) and unclip the clevis pin for the slender seatbelt shoulder height adjuster wire Photo-2 and let it hang free. Unplug the wire harness & the seat is free to come out. I'm not sure about later models, but you might have to disconnect the battery if the seat is wired to the SRS to avoid tripping a fault in the SRS memory which requires a trip to the dealer to reset (also have radio code handy if you disconnect the battery).
http://www.nmia.com/~dgnrg/page_11.htm

[G46]

Just try it, should work also, the main difference between LKM- L and B is, that L checks the bulbs in cold and warm condition while the LKM-B only checks the bulbs in warm condition = when the lights are on.
Front seat removal is partly shown here http://bmwe32.masscom.net/sean750/Se...atSwapping.htm

Front seats have two bolts at the back and they are hooked in at the front.
You will need to remove these two bolt and also disconnect the seat belt ( 1 bolt at the side of each seat) and the tensioner cable under the seat. If you have heated or electric seats you will also need to unplug them underneath.
Once all are undone tilt the seat forward from the top to unhook it from the front. You might have to tilt forward first then pull it back towards you from lower down the seat back

Here with pics: Getting the seat out is straight forward: pop the headrest out, slide the seat forward, remove the two Torx bolts Photo-1 & Photo-1a in the rear & tilt the seat forward to disengage the front hooks Photo-1b. A 7/16 or 11 mm 12-point socket fits the Torx heads if you don't have a Torx "E14" socket. Remove the seatbelt bolt (also Torx E14) and unclip the clevis pin for the slender seatbelt shoulder height adjuster wire Photo-2 and let it hang free. Unplug the wire harness & the seat is free to come out. I'm not sure about later models, but you might have to disconnect the battery if the seat is wired to the SRS to avoid tripping a fault in the SRS memory which requires a trip to the dealer to reset (also have radio code handy if you disconnect the battery).
http://www.nmia.com/~dgnrg/page_11.htm

thanks Shogun, i will do it after i rectify another issue, currently my alternator is producing 18v during acceleration, 14.3 during idling. im not running it yet and purchased a new VR, once im done with the alternator, i will get back to this license plate light issue.

[G46]

so, ive done on the VR replacement whilst the alternator is still in the car, kinda PITA but still doable.

now back to license plate light issue, i did pull each fuse, and none of them turns off the light, took out the LKM, yes it will turn off every light.

havent measured pin 14 on X12 yet

[G46]

just to double confirm, pulled every fuse, the light did not turn off, trace the wiring, ends up under the LH front seat, which i cant really remove, i disconnected the light switch, license plate light still lit up. if i remove LKM, it will turn every light off, i will measure pin 14 on x12 later after work. apart from that, any other idea?

[E32FAN]

just to double confirm, pulled every fuse, the light did not turn off, trace the wiring, ends up under the LH front seat, which i cant really remove, i disconnected the light switch, license plate light still lit up. if i remove LKM, it will turn every light off, i will measure pin 14 on x12 later after work. apart from that, any other idea?

Salut G46,

When you say "pulled every fuse", are you referring to both the front and rear (under left rear seat) power boxes?

Just asking.

[G46]

Salut G46,

When you say "pulled every fuse", are you referring to both the front and rear (under left rear seat) power boxes?

Just asking.

ahh, i forgot about the fuses under the rear seat, i will try and do that later.

[G46]

I just pull out the fuses at the back one by one, still lit up, i measured pin 14 on x12, yes theres supply, now my brake light stays on also. I am believing now my brake light wirings under the dash, for the brake light switch is somehow messed up..

[E32FAN]

I just pull out the fuses at the back one by one, still lit up, i measured pin 14 on x12, yes theres supply, now my brake light stays on also. I am believing now my brake light wirings under the dash, for the brake light switch is somehow messed up..

Your engine is M60 so we should use the USA ETM for 1993.

On page 0680-01 you can see that Pin 14 of the D100 Data Link Connector is wired directly, protected only by Fusible link A, to the battery!

When you remove the D100 cap, do the lights go out? See page 7100-02 Fig 2. This is a familiar story - "E32 Fire Warning" thread started on 06-21-2018.

Your car may have some melted conductors inside the harnesses, causing your odd symptoms.

[G46]

Your engine is M60 so we should use the USA ETM for 1993.

On page 0680-01 you can see that Pin 14 of the D100 Data Link Connector is wired directly, protected only by Fusible link A, to the battery!

When you remove the D100 cap, do the lights go out? See page 7100-02 Fig 2. This is a familiar story - "E32 Fire Warning" thread started on 06-21-2018.

Your car may have some melted conductors inside the harnesses, causing your odd symptoms.

i will try to remove diagnostic cap later after work. and will come back here to update the result

[G46]

Update: i removed the diagnostic cap, it wont turn the license plate light + brake light did not turn off unless i pull out the LKM