91 735il When foglights on 3 Turn Signals Stay Solid and Fog Lights Don't Work.

[Highschool735il]

Hey everyone I have a weird problem with my 1991 735iL. If i turn my driver side turn signal on while foglights are off all of the interior lights flash with it such as ac buttons, emergency flasher button, the sun blocker lights, but besides the interior lights flashing it works as expected. Sound comes on, turn signal flashes on dash and actual turn signal flash on outside of car. This only happens with the driver side.

However, when I turn on the fog lights (turn signal not activated just turned on fogs) the drivers side turn signal light comes on solid on the dash. All turn signals except passenger rear are turned on solid on the outside of the car and the fog lights do not turn on. When I activate a turn signal with fog lights on there is no sound however they do flash on the outside of the car. (Turn signal on outside of car is still solid but the flash makes the turn signal flash a little brighter so you can tell it's flashing.)

I've tried disconnecting all the bulbs one by one to see if anyone disconnect solves the problems however it did not change anything. I just got the car and I've found some aftermarket wiring in it so is it possible they somehow wired the fog lights to the turn signals? I also pulled out the fog light bulbs and they seem to be low beam headlight bulbs. Could the use of a wrong bulb cause this problem?

Any help would be greatly appreciated as it is stumping me.
Thank you!

[XAlt]

LKM or mustard is my guess.

Fog lights are H1s, dunno how'd you hack up a pair of 9006s in there.

[Highschool735il]

Thanks for the help I really appreciate it!
The car used to be my grandfathers and it seems like he did have some shady work done to it. It seems like someone used some butt connectors to I guess change the lightbulb adapters from H1s to 9006s but they're definitely 9006s in there. Because you mentioned that I'm now guessing when they rewired the fogs they probably messed something up with is causing the problems.
Thanks again!

[e30luv318i]

H1 are projector fogs 9006 are free form fogs

[shogun]

Mustard relay is only for Tail Light / Parking Light http://bmwe32.masscom.net/sean750/mu...stardRelay.htm
LKM = light control module is for hi beam, low beam, front foglight and on EURO models rear foglights, it has 3 respectively 4 relays only inside.

[Highschool735il]

Thank you guys for the help!

Mustard relay is only for Tail Light / Parking Light http://bmwe32.masscom.net/sean750/mu...stardRelay.htm
LKM = light control module is for hi beam, low beam, front foglight and on EURO models rear foglights, it has 3 respectively 4 relays only inside.

Hey Shogun,
When I turn on my fogs after less than a minute while driving the dash will beep and display either Parking Light or Brake Light Switch. Do you have any idea if this might be connected to the turn signal problem? Does that sound like the mustard relay might be dead?

When fogs are turned off all lights work perfectly no problem it's just when I turn the fogs on.
Thanks!

[shogun]

Tail Light / Parking Light Messages =Mustard Relay.
Brake light switch is a different story, I assume you mean "Brake Light Circuit" http://www.nmia.com/~dgnrg/page_25.htm
https://www.bimmerforums.com/forum/s...ht=brake+light

[Highschool735il]

Tail Light / Parking Light Messages =Mustard Relay.
Brake light switch is a different story, I assume you mean "Brake Light Circuit" http://www.nmia.com/~dgnrg/page_25.htm
https://www.bimmerforums.com/forum/s...ht=brake+light

I believe you are assuming correctly because I can't quite remember haha it was Brake Light something. I'm looking into the mustard relay now and it seems to be the explanation to a couple of my problems such as dash lights. Thank you all for the help I greatly appreciate it!

[shogun]

Try to learn how to read European wiring diagrams
Good article here under electronics: Understanding European wiring diagrams (PDF) http://www.e38.org/e32/

[E32FAN]

Hey everyone I have a weird problem with my 1991 735iL. If i turn my driver side turn signal on while foglights are off all of the interior lights flash with it such as ac buttons, emergency flasher button, the sun blocker lights, but besides the interior lights flashing it works as expected. Sound comes on, turn signal flashes on dash and actual turn signal flash on outside of car. This only happens with the driver side.

However, when I turn on the fog lights (turn signal not activated just turned on fogs) the drivers side turn signal light comes on solid on the dash. All turn signals except passenger rear are turned on solid on the outside of the car and the fog lights do not turn on. When I activate a turn signal with fog lights on there is no sound however they do flash on the outside of the car. (Turn signal on outside of car is still solid but the flash makes the turn signal flash a little brighter so you can tell it's flashing.)

I've tried disconnecting all the bulbs one by one to see if anyone disconnect solves the problems however it did not change anything. I just got the car and I've found some aftermarket wiring in it so is it possible they somehow wired the fog lights to the turn signals? I also pulled out the fog light bulbs and they seem to be low beam headlight bulbs. Could the use of a wrong bulb cause this problem?

Any help would be greatly appreciated as it is stumping me.
Thank you!

This is a good puzzle! I suppose there must be not 1 fault but 2, which always confounds matters!

1. Fog circuit must be shorted to left turn indicator circuit. TURN is BLU/GRN. FOG is YEL/GRY

2. Left turn indicator circuit must be shorted to interior light circuit.

As shogun says, European Schematic Diagrams are at: http://shark.armchair.mb.ca/~dave/BMW/e32/e32_91.pdf

Fog circuitry shown on Page 6313-01 and -05.

Turn circuitry shown on Page 6312-00 to -04.

The S18 Hazard Switch Pin 5 carries the Left Turn circuit, and Pin 4 carries the interior lighting circuit. So if pins 4 and 5 happen to be shorted together, then your interior lights symptoms would happen.

Just a thought. I would remove the Hazard Switch and see if the symptoms are altered.

The turn click sound is created by a "relay" inside the Instrument Cluster, whose only function is to click (it has no switched contacts). It is simply wired to the IC turn indicators.

You can certainly track these shorts down, if you are methodical (and you seem to be).

Can you get a DC current clamp-on Ammeter? They are available, but rare. Lots are on eBay from China.

You can use a DC Ammeter to track the path of a DC short circuit current flow, down to the location of the short.

[Highschool735il]

Thank you Shogun I'll look into that. I very much appreciate the help!


Thank you so much E32FAN for all the information! I take auto tech (mechanics) in school so the shop there probably has a DC ammeter I'll ask my teacher. I'll look into everything you said and get back to you. Again thank you! Like you said it is a good puzzle and I'm having trouble with it so I really appreciate it!

[Highschool735il]

This is a good puzzle! I suppose there must be not 1 fault but 2, which always confounds matters!

1. Fog circuit must be shorted to left turn indicator circuit. TURN is BLU/GRN. FOG is YEL/GRY

2. Left turn indicator circuit must be shorted to interior light circuit.

As shogun says, European Schematic Diagrams are at: http://shark.armchair.mb.ca/~dave/BMW/e32/e32_91.pdf

Fog circuitry shown on Page 6313-01 and -05.

Turn circuitry shown on Page 6312-00 to -04.

The S18 Hazard Switch Pin 5 carries the Left Turn circuit, and Pin 4 carries the interior lighting circuit. So if pins 4 and 5 happen to be shorted together, then your interior lights symptoms would happen.

Just a thought. I would remove the Hazard Switch and see if the symptoms are altered.

The turn click sound is created by a "relay" inside the Instrument Cluster, whose only function is to click (it has no switched contacts). It is simply wired to the IC turn indicators.

You can certainly track these shorts down, if you are methodical (and you seem to be).

Can you get a DC current clamp-on Ammeter? They are available, but rare. Lots are on eBay from China.

You can use a DC Ammeter to track the path of a DC short circuit current flow, down to the location of the short.

You my friend are a life saver! You were correct. 2 pins inside the hazard switch were shorting out together. I put them back in their place and locked them in and no turn signal on dash, no flashing interior lights, (however half the dash is still dark. my guess is it needs new bulbs seeing as the car has 257k) clicking sound for turn signal came back, and the rear solid turn signal is not solid anymore. So only problem left is fog lights dont turn on but when you switch them on front turn signals come on solid.
I did some testing with my multimeter and when fogs are not switched on they're receiving about 8.3v and when they're switched on they receive around 9.4v. So somehow it's missing about 2 1/2 volts.

Thank you so much I appreciate all the help!

[E32FAN]

I did some testing with my multimeter and when fogs are not switched on they're receiving about 8.3v and when they're switched on they receive around 9.4v. So somehow it's missing about 2 1/2 volts.

I'm glad to hear of your success!

Have a look at Page 6313-05. There you can see relay K3 inside the A3 Lamp Control Module LKM. When K3 is energized, 12V flows through F7 to pin 17. Then out through pins 16 and 32 to the left and right fog lights. If you measure these voltages, do you find 9.4 or 8.3 volts?

You can loop thin bare test wires around the LKM pins to make these measurements. The pin numbers are molded into the LKM housing.

[shogun]

Here a pic of the LKM installed without cover for testing, there you can see what is K3 http://www.bimmerboard.com/members/s...egung_engl.jpg
This is the EURO LKM with 4 relays, U.S. and Japan version has only 3 relays as the rear foglight relay is missing there. With this 'open' installation oneu can even squeeze the contacts together of the relays to see if that is the problem when lights are not working, I bent my ones slightly and they last a long time since then.
The LKM has 2 output contacts for low beam lights.

LKM and CCM pinout http://www.bimmerboard.com/forums/posts/1175396/

I hope I made no mistaktes, E32Fan, you are the electronic master.

[Highschool735il]

I'm glad to hear of your success!

Have a look at Page 6313-05. There you can see relay K3 inside the A3 Lamp Control Module LKM. When K3 is energized, 12V flows through F7 to pin 17. Then out through pins 16 and 32 to the left and right fog lights. If you measure these voltages, do you find 9.4 or 8.3 volts?

You can loop thin bare test wires around the LKM pins to make these measurements. The pin numbers are molded into the LKM housing.

Sorry for the very late response school has been keeping me away from the bmw
I measured the 2 pins and they had 0v each... However when i manually moved the contacts on the relay with a very small pick the voltage jumped to around 11.7v (sorry I was in a rush so not sure of exact measurement.) So would maybe bending the relay contacts a little as shogun mentioned help at all?

Thank you both for your time and very helpful information I really appreciate it!

[shogun]

E32Fan will give you more details, he is the specialist.
I can only tell you it helped in case of my problem, when 1 headlight low beam was not working, I cleaned the contacts of the K1 relay in the LKM and rebend a bit so that the contact was better, and problem was solved.

[E32FAN]

Yes, bending the contact arms will help.

The contacts will be pitted and burned, so there are carbon deposits that block the current flow.

You can buff the contacts clean with very fine sandpaper.