Interior lights not working

[Coyote_ar]

Hi everyone, i got a '89 525i (M20 AT).


Every electrical part of the car is working just fine, except for the interior lights. I got light in the trunk, got light in the license plate, got light on the instrument panel. But nothing on the interior.
I've measured and there is no 12v. I checked the Bentley manual, and it listed about 6 fuses to check for interior lights. All fuses, both in the front and rear compartments are fine, no blown fuses nor wrong values. I even removed the fuses and checked that the contacts werent dirty.


Any idea what else i can check? is there any relay or module that affects the interior lights?


Thanks for your help.

[shogun]

Check the connection of the interior main light and the switch, have seen some of these switches burnt, the light next to the interior mirror. Intwerior light is controlled by the GM under rear seat

[shogun]

Just found my old post with the pics http://www.bimmerboard.com/forums/posts/1245379/
Other posts:

Subject: Interior lights Author: leersmd Posted on: 2006-07-10
The main interior lights would not always go on when I opened the doors, but if I hit the 3 pos switch, they would illuminate. I took the light assembly apart and found the plastic tabs on the switch had worn down and were not making depressing the contacts fully. Fortunately, I had a spare light assembly and swapped the switch out. Solved the problem. Keep in mind, I could get the lights to come on by touching the switch but they would not be on every time I opened the door until I replaced the defective switch - I don't know if you've tried to manually push the switch to activate the lights.
------------------
I took the entire front interior light assembly down, pulled the buttons off (if I remember correctly), and then just bent out the metal contacts a bit more. They've been fine for about a month so far. Rob, 1994 740i

[Coyote_ar]

Hi Shogun, thanks for your reply. Actually the switch seems to be fine, but just in case that was the problem i tried disconnecting the whole lamp, and measure the 4 pins directly from the connector. i tried all combinations, and neither is showing 12v.

Today i removed the rear fuse box cover, found out a set of 4 fuses i didnt see before. one was blown, it was the one corresponding to the rear defroster. since i recently bought the car, and we were in summer i never noticed that the defroster wasnt working. the light was coming up in the dashboard, but the defroster wasnt working. now with the new fuse, its working again. so i guess thats a positive thing, didnt fix the light issue, but at least thats working :P

I removed every relay, and every fuse. checked that the fuses were ok with a tester ... just in case they were blown but looked ok. but all of them were good. the only thing that is a bit weird, is that in the graph i have on the rear fuse cover. it says that fuse 30 corresponds to interior lights. yet i have no fuse 30 ... the slot is empty and there are no connectors there. is this normal?

i've been trying to understand the schematics shown here:
http://download.golgofa.ru/valera/ETM/bmw_e34_520_low_ETM/6330.0/index.html

Any chance that the ZKE or GM are defective? is there something that can be fixed inside them like the deal with the LKM?

But thats a bit over what i can understand. Car wiring is hell, id rather rebuild an engine than fix a light :P

[shogun]

see here , it says 30 and some others are not used http://download.golgofa.ru/valera/ETM/bmw_e34_520_low_ETM/0670.1/index.html
But that5 link you gave it that the correct built year wiring diagram? You say 1989, which month?

What country spec is your car? The wiring diagrams are probably USA spec. Check here once more with other wiring diagrams http://shark.armchair.mb.ca/~dave/BMW/

this would be 1989 E34 and there is fuse 30 http://shark.armchair.mb.ca/~dave/BMW/e34/e34_89.pdf
but that is 7.5 A
door lock heating
central locking
power windows
sunroof
ZKE
telephone

Resetting the GM also sometimes helps. New General Modules (GM)

MODELS: 7 Series (E32), 5 Series (E34) - Vehicles produced 9/91 and later
Situation: New general modules have been used in production since September 1991 in all E32 and E34 models. The software has been completely revised (details of these revisions are found in the attachment to this Service Information Bulletin). Part numbers have been changed to reflect these revisions, as listed below, as of September 1991. Model Part Number
E32 61 35 8 356 095, E34-up to 61 35 8 356 095 9/91 production, E34-9/91 and later production 61 35 8 355 812
Note:
E34 vehicles produced 9/91 and later have different central locking system components from earlier E34 vehicles; therefore, P/N 61 35 8 355 812 is used only in E34 vehicles produced 9/91 and later, P/N 61 35 8 356 095 can be used in E34 vehicles produced prior to 9/91, and in all E32 vehicles. When the general module is connected to the vehicles electrical system, it will recognize (and store in memory) the vehicle configuration, such as:
- with/without power windows
- With/without power sunroof
- with/without wiper contact pressure control
- with/without headlight washers
Important Information
All general modules must be plugged in only after disconnecting the vehicle's battery. If the vehicle's battery is connected when the GM is installed, undefined signal contacts can cause an incorrect vehicle configuration to be stored, resulting in the impairment of one or more of the above-mentioned systems. If one or more of the GM functions are impaired in this matter, the GM can be "cleared" by disconnecting the vehicle's battery for at least ten seconds.

GM Function Changes E32/E34 (Beginning with 9/91 Production)
- Repeat and Time interlock for headlight washers:
· Time interlock: 3 minutes
· Headlight washing at fifth windshield washing after time interlock.
- Intensive washing pump operating time reduced from 3 to 2 seconds
- Minimum interval for intermittent wiping is programmable down to 2 seconds (previously 3 seconds)
- Increased wiper contact pressure during windshield washing cycle is now also provided during dry wiping portion of the cycle (previously only during washer pump operation).
- Previously, the GM would react to opposing signals (eg., an unlock signal while trying to lock, as with a defective microswitch) by carrying out the first command, then the opposing command (e.g., locking, followed immediately by unlocking).
Repeating the first command then results in carrying out that command (e.g., try to lock again, and locking is now carried out).
This function ("Asynchronous Position") is omitted in the new GM for all E32 models and E34 models prior to 9/91 (P/N 61 35 8 356 095), and remains in the new GM for E34 models after 9/91 (P/N 61 35 8 355 812) only for central locking commands "lock" and "double-lock".
- After unlocking is performed due to crash sensor activation, the locking command is now reactivated by double-locking with the key from either the driver's or passenger's door.
- The "one-touch" operation of windows has been expanded to include all four windows in the opening direction. The driver's window still has "one-touch" operation in both opening and closing directions. Interruption of the "one-touch" feature of the driver's window in the closing direction is still accomplished by depressing any window switch (in any direction), or by depressing the sunroof switch in the "tilt" direction (provided the sunroof is not already in the "tilt" position). Interruption of the "one-touch" feature of the sunroof in the closing direction is still accomplished by depressing the sunroof switch (in any direction).
- The switch-off delay of the interior lights which occurs after entering the vehicle and closing the driver's door has been reduced from 20 seconds to 15 seconds.


Be very careful with the rear window heating, some had fires in the fuse box http://www.bimmerforums.com/forum/showthread.php?2024379-E32-fuse-box-fire-under-rear-seat-pics&highlight=fire+rear+seat
clean all contacts of fuses, relay etc.

[Coyote_ar]

This is the Info of my car.






Vehicle information





VIN long
WBAHC210904237760


Type code
HC21


Type
525I (EUR)


Dev. series
E34 ()


Line
5


Body type
LIM


Steering
LL


Door count
4


Engine
M20


Cubical capacity
2.50


Power
125


Transmision
HECK


Gearbox
AUT


Colour
ROYALBLAU METALLIC (198)


Upholstery
INDIGO LEDER (0293)


Prod. date
1988-11-14






Order options



No.
Description


200
KATALYSATOR - ENTFALL


226
SPORTS SUSPENSION SETTINGS


314
HEATED WINDSCREEN WASHER NOZZLES


355
LAMINATED GLASS


401
SLIDING/VENT ROOF, ELECTRIC


411
WINDOW LIFTS, ELECTRIC


498
HEADRESTS IN REAR, MECHANIC. ADJUSTABLE


534
AUTOMATIC AIR CONDITIONING


553
ON-BOARD COMPUTER IV W REMOTE CONTROL


570
STRONGER ELECTRICITY SUPPLY


651
BMW Bavaria C Reverse


823
HOT CLIMATE VERSION



The item that said that fuse 33 (its 33 not 30 the one thats missing, my bad) was for interior lights, was actually the rear fuse box cover. thats what was weird, cause for fuse 45, which is empty, the list show an empty line. but for 33 i got "interior light, floor lights, glovebox and trunk lights, radio and power plug" (which btw, glovebox trunk radio and power plug all work just fine).
This is the rear fuse cover (in spanish)
http://i67.tinypic.com/2d9tykn.jpg

And this is the fuse box itself
http://i68.tinypic.com/2jb5p9l.jpg

As for the rear fuse box fire ... yeah it looks pretty dangerous back there. specially since i had a hard time removing the seat for the 1st time. in case of a fire that place is really hard to access.
Luckily for me, it was nothing as serious as the ones you posted on that thread.
I cleaned the contacts and measured that all fuses were ok before putting them back on.
the fuse that blew, was really burnt.
http://i64.tinypic.com/qox6yq.jpg

Plus that was under the plastic cover, so getting there took quite a while. I think i will leave the rear fuse box cover with no bolts this time ... just in case i need to access there in a emergency.

[Coyote_ar]

Im out of ideas, anyone know how the lights are wired to the rear lights? which of this cables goes to the back?
http://www.bimmernut.com/forum/attachment.php?attachmentid=8470&stc=1

Im thinking maybe just re doing the wiring for the light panel on the top, wiring some 12v in there (removing the old cables), and just have light when i flip the switch. Dont have the doors switch, but at least some light.

[shogun]

You have to check in the 1989 wiring diagram I posted above already.
In any case, interior light is controlled by the general module under rear seat and the relay module next to it.

[genphreak]

Clearly you have an overheating fuse. It may only get hot for short periods, i.e. when you use a particular device, such as a power window, or a light, or a radio accessory.

I would:
1. Remove/disconnect any non-factory devices (old cellular car-kits, alarms, radios, amps)
2. Re-fit the factory rated fuse/s
3. Use a multimeter with a clamp ammeter (cheap form china) to find current draw that exceeds expected levels. Doing this will help you find the short/faulty component- if there is one.

9 times out of 10 these things are caused by poor accessory installation or worn wiring insulation (common in the trunk harness, lie in the trunk and unbind the trunk harness under the parcel shelf, looking for broken and frayed/shorts where it curls under the parcel shelf.

[Coyote_ar]

i dont have lights at all, not sometimes. not even after having the car off for several days i wont have lights at all. neither on automatic nor manual mode. i even tested for 12v on the plug for the whole light module, there is just no power there.

as per the list on the cover of the rear fuse box, fuse 33 should be the one related to interior lights, glove box light and trunk lights. both the glove box and trunk lights are working. but the fuse 33 is not there in the rear fuse box. im wondering if for some reason the removed the fuse cabling from there and relocated it somewhere along the wiring.

the only non factory device the car had, was a cd player in the trunk. im trying to see if those 3 ugly wires with tape are part of that installation. (this is the only clue to follow up).

i have checked all fuses, in both front and rear boxes, removed them, checked for continuity, checked for clean contacts and verified that they had the proper rating.

the weird thing is that aside from this issue, the rest of the car works perfectly. i even found out that i have automatic heated side mirrors, after changing the fuse that was blown up, now those started working as the rear window.

[whiskychaser]

I realise it says 'interior light' for fuse 33 on that cover but that is at odds with the wiring diagram. According to that, power for the interior lights comes from fuse 21 in the front fuse box. Maybe check that fuse and that there is continuity between the fuse holder and the white plug X336? Looks like the red/white line is the one you need. FWIW, the diagrams don't show a fuse 33

[genphreak]

It may be the LKM/Light Control Module (front eBox)

May well have cracked or dry joints. but you have to be positive first that it is not the trunk harness shorting. It has the fader circuit in it which always fails as they age- not sure what component but maybe it needs an old capacitor/s replaced?

[Coyote_ar]

I realise it says 'interior light' for fuse 33 on that cover but that is at odds with the wiring diagram. According to that, power for the interior lights comes from fuse 21 in the front fuse box. Maybe check that fuse and that there is continuity between the fuse holder and the white plug X336? Looks like the red/white line is the one you need. FWIW, the diagrams don't show a fuse 33

As per the schematics posted above, on page 6330.0-03
http://download.golgofa.ru/valera/ETM/bmw_e34_520_low_ETM/6330.0/index.html

It looks like the fuses on the front box related to interior lights are 18 and 21. now fuse 18 seems to be related to the map lights for the rear lights, i dont have those.
if im not mistaken, x338 is the 4 pin plug that i put the photo before, the one next to the roof motor.

So if im reading this correctly, if i short pins 1 and 4 of the x338 with a wire, the lights in the back should come on. if i measure with the tester pins 1 and 2 on x338, i should have 12v (which i dont).

I will remove the fuse 21, and measure for continuity between there and the pin 2 of x338. that and jumping 1 and 4 to see if the lights in the back come up.


It may be the LKM/Light Control Module (front eBox)

May well have cracked or dry joints. but you have to be positive first that it is not the trunk harness shorting. It has the fader circuit in it which always fails as they age- not sure what component but maybe it needs an old capacitor/s replaced?

I have worked on the LKM module for the hi and low front lights, but i dont see any schematic referring to it as related to the interior lights. as for the trunk harness, where is it ? (yeah i know, in the trunk :P ) I mean its the one going to the trunk lights, or the stop lights? i believe those 2 circuits are separated from each other. got more info on this?

thanks everyone for your help.

[shogun]

LKM is only for dip beam, high beam, front foglights, rear foglights, EURO models have 4 relays inside the LKM because they have rear fogs, while US LKM have 3 relays because no rear foglights.
Interior lights is controlled by the GM general module via the RM relay module.

[whiskychaser]

Your link doesn't appear to be for the 525i but I think it is correct. If you connect pins 1&4, you wont get anything - 1 goes to ground and 4 is a ground link to the interior lights. Pin 2 is the live in and pin 1 is the manual ground so you should read 12V across them. But you need to make sure pin 1 IS connected to ground. I expect it probably is but I wouldn't take it for granted

[Coyote_ar]

If you connect pins 1&4, you wont get anything - 1 goes to ground and 4 is a ground link to the interior lights. Pin 2 is the live in and pin 1 is the manual ground so you should read 12V across them. But you need to make sure pin 1 IS connected to ground. I expect it probably is but I wouldn't take it for granted

1 goes to ground, 4 is a ground link for the rear lights. but on the input side of the rear lights you got +12v coming from the fuse 21. shorting 1 and 4, would be the equivalent of putting the light switch of the front lamp in position 1 (manual). by shorting 1 and 4 i would avoid the whole front lamp module, and test the remaining part of the circuit. if i do get light in the back by doing this test. i know that at least that part of the circuit is working. the purpose of this test is to be sure that the power feed and cabling are ok.

indeed pin 1 needs to be grounded, but im inclined to believe thats not the problem. because pin 1 is only used for the manual position. once you switch to the automatic position, the grounding is done by the circuit passing through the relay module module controlled by the GM module. right now neither of the 2 positions work.
so basically the options are:
1) there is a common problem to both positions, likely being whats between fuse21 and the lamps.
2) there are 2 different problems, one affecting the manual position, and one affecting the automatic one.

hopefully its case 1, its easier to troubleshoot a single problem :P

gonna go check that out.

[whiskychaser]

Yes, shorting 1&4 would work if you have a live to the rear lights on the auto side. I'm suggesting checking pin 1 is connected to ground as it is simple to test. So is checking that you get a ground at pin 3 when the door is open (via the RM and GM). If you have the grounds, you know you are missing the live for some reason and can concentrate on that. As you say, it is easier to troubleshoot one thing at a time

[Coyote_ar]

ok, found the problem. i removed F21, connected the + terminal to a long cable, and jumped it to pin2 of the light plug. Lights are on, in both positions of the switch (so GM, RM and door switches are working just fine, yay!).

The problem is between F21 and the pin2 of the light plug. Specifically, before the cables split going to the back lamps.

Since my car had a CD changer in the back, im thinking they use the lights +12v cabling to feed that (a really profesional installation indeed). I'll have to go all over that messy installation to find out where that orangutan of an electrician messed up the installation. Im betting theres some twisted cables with tape around somewhere, and thats messing with the power to the lights.

Well, at least i know where the problem is, it should be fine once i find that bad connection and fix it. Thanks everyone for your help.

[632 Regal]

The wiring harness in the trunk runs along the hinge bracket. Carefully move it away from the bracket and unwrap the tape. There is almost always something interesting to look at in that bunch of wires.