Author Topic: Fog light install (91 318is) help, please (Read 10088 times)

m42 fan · « **Reply #15 on:** September 23, 2006, 07:00:31 AM »

That's the correct plug. A two button switch will work fine, that's what I'm using. You could even wire the other button up to whatever you wanted to. I use mine to raise and lower my radio antenna.

After thinking about your problem, you might want to try to replace your relay with one that is known to be good (i.e. came off another car with functioning fogs), just to rule it out as a problem. I'm about 75% sure that's where your problem lies.

Brian

melloh · « **Reply #16 on:** September 24, 2006, 03:47:32 AM »

Cool. Thanks Brian for keeping up w/ this. (I MUST be doing something wrong.) Ok, so anyone in the bay area want a free beer? What's the trade-off? I get to throw your relay in and see if it works, of course! The relay I have is brand new (the one does nothing). Is there a way to test the wiring in the plug to see if power is runnin gthrough it?

m42 fan · « **Reply #17 on:** September 24, 2006, 07:37:56 AM »

Yes, you absolutly can and should check to see if you have power at the plug at the appropriate times. Get the E30 Bentley and your meter, and go to town.

OK. I just dug out my Bentley. You want Figure 10-2 on page 33 of the Electrical chapter, which is the last one in the book. That's the diagram of the headlight circuit for cars without check controll panels. Even better would be page ELE-182 from the E-36 Bentley, which is the Headlight/Foglight page for 1992-1994 E-36's, and is close enough to our cars to troubleshoot from, aside from being much more detailed.

Long story short, the plug that coresponds to pin 30 on your relay should be hot at all times.
the plug that corresponds to pin 87/87b is your output to the foglights. This one will have power whenever your lights are actually on.

Pins 86 and 85 are the ones that actually controll the relay. This is where all the action is. 86 is your input, and 85 is your output. Let me give you a quick and dirty into how a relay works. When there is a voltage drop between pins 86 and 85, the relay electrically closes the contacts between pins 30 and 87, which routes the actual power to your lights. Without that voltage drop at the appropriate times, there can be no light. So, what we want to see is a voltage present on pin 86 whenever your headlights and key are on. Pin 85 should show ground potential (0 volts to ground) at all times except when your high beams are on, when it should show a voltage.

If you have the conditions I just described, then Congratulations! We just isolated your relay as the culprit. If you have something else, then it's time to keep troubleshooting. I gave you everything you need to know, but I would strongly suggest you get a copy of that page out of the E-36 Bentley. It will def. help your understanding of the circuit.

Let me know how it goes

Brian

melloh · « **Reply #18 on:** September 24, 2006, 05:08:16 PM »

HL= headlights
HB = High Beam
FS = Fog Switch
FL = Fog light

First, I tested for voltage @ the plug for the switch. Note - for everything it is w/ Key in ON position. The results were identical for both FL relays:

HL OFF
0.00v

HL ON
0.22v +/- .01

Then, I ran the relay test.

Situation 1: w/ new HELLA relay (as in picture) PN: 61.311.374.631 (This is when I cannot get FL on at all)
Notes:
+ = clearly showed voltage (10-12.5v)
- = -.04-.04v
# = I displayed the number output on multimeter when voltage was > .05v

HL relay:
.....HL-OFF...HL-ON....HB - ON
30... + .......... + ........... -
85... + .......... - ........... -
86... + .......... + .......... +
87... - .......... + .......... .08

FL relay:
.....HL-OFF...HL-ON...HB - ON....FS - ON
30... + .......... + ........... + ......... +
85... - .......... + ......... 0.08 ....... +
86... - ......... 0.11 ......... - ........ 0.11
87... - .......... - ............ - .......... -

Situation 2: W/ generic (lime-green 5 prong w/ middle prong broken off PN: 61.368.375.700 - TYCO w/ BMW stamp) or orange headlight relay (when fogs would turn on w/ headlights even w/o switch attached)

HL relay:
.....HL-OFF...HL-ON...HB - ON
30... + .......... + ........ -
85... + .......... - ........ -
86... + .......... + ....... +
87... - .......... + ..... 0.08

FL relay:
.....HL-OFF...HL-ON...HB - ON
30... + .......... + ........ +
85... - .......... + ....... 0.07
86... - ......... 0.08 ..... -
87... - .......... + ....... -

And now to add to the confusion... just to check again, I pulled the switch while HL on & FL on and FL went out this time. So, I turned everything off again, put the switch back, and the fogs would not turn on again at all. Very strange. Checked fuses - OK. Maybe I burned the bulb. Just added as a side note.

If nothing can be figured out from this, then I may as well just give up and live w/ my fogs being on all the time and perhaps start wiring so they stay on w/ HB. Thanks again for all your time!

ak96ss · « **Reply #19 on:** September 24, 2006, 05:40:14 PM »

Quote from: melloh

HL= headlights
HB = High Beam
FS = Fog Switch
FL = Fog light

First, I tested for voltage @ the plug for the switch. Note - for everything it is w/ Key in ON position. The results were identical for both FL relays:

HL OFF
0.00v

HL ON
0.22v +/- .01

Then, I ran the relay test.

Situation 1: w/ new HELLA relay (as in picture) PN: 61.311.374.631 (This is when I cannot get FL on at all)
Notes:
+ = clearly showed voltage (10-12.5v)
- = -.04-.04v
# = I displayed the number output on multimeter when voltage was > .05v

HL relay:
.....HL-OFF...HL-ON....HB - ON
30... + .......... + ........... -
85... + .......... - ........... -
86... + .......... + .......... +
87... - .......... + .......... .08

FL relay:
.....HL-OFF...HL-ON...HB - ON....FS - ON
30... + .......... + ........... + ......... +
85... - .......... + ......... 0.08 ....... +
86... - ......... 0.11 ......... - ........ 0.11
87... - .......... - ............ - .......... -

Situation 2: W/ generic (lime-green 5 prong w/ middle prong broken off PN: 61.368.375.700 - TYCO w/ BMW stamp) or orange headlight relay (when fogs would turn on w/ headlights even w/o switch attached)

HL relay:
.....HL-OFF...HL-ON...HB - ON
30... + .......... + ........ -
85... + .......... - ........ -
86... + .......... + ....... +
87... - .......... + ..... 0.08

FL relay:
.....HL-OFF...HL-ON...HB - ON
30... + .......... + ........ +
85... - .......... + ....... 0.07
86... - ......... 0.08 ..... -
87... - .......... + ....... -

And now to add to the confusion... just to check again, I pulled the switch while HL on & FL on and FL went out this time. So, I turned everything off again, put the switch back, and the fogs would not turn on again at all. Very strange. Checked fuses - OK. Maybe I burned the bulb. Just added as a side note.

If nothing can be figured out from this, then I may as well just give up and live w/ my fogs being on all the time and perhaps start wiring so they stay on w/ HB. Thanks again for all your time!

Does your low beam relay only have 4 lugs on it?

It's raining out now, or I would check mine, but I believe the low beam relay should have 5 lugs.

I would also verify that you have continuity on your grounds from the foglight plug.

More later - I have to make dinner for the kids right now...

melloh · « **Reply #20 on:** September 24, 2006, 10:25:42 PM »

Yessir. Only 4, and the fifth (middle) would have nowhere to go. I can take a pic tomorrow if needed. In fact, the 'generic' TYCO relay i mentioned came w/ 5, but i had to pull the middle off so it would go in.

How would I check for this continuity? Yes - I AM a greenhorn (sorry).

Henry

(thanks for replying, btw)

m42 fan · « **Reply #21 on:** September 24, 2006, 10:28:31 PM »

Hmmmm.....
I think we may be on to something. Pulling out pins from a generic relay = a good sign we've found your problem. Pick up a real lowbeam relay and try it. I'm now about 95% sure this is your problem.

Brian

ak96ss · « **Reply #22 on:** September 24, 2006, 11:26:40 PM »

AND.... to add to the mix....

If your hi-beam relay pin 87a is not getting +12V when the low beams are on, the fog light relay won't close and your foglights won't work either.

[EDIT: foglight switch should be on for the above]

To check for continuity, set your VOM to ohms to measure resistance; one lead goes to the brown wire on the foglight connector, the other to ground (there is a ground stud behind the headlights, or you should be able to just connect it to the engine). The resistance should be at or very very near 0 ohms.

[EDIT again: I would definitely make sure that the pinout of your relays match the pinout of the factory relays - standard automotive relays will physically fit, but the pinout is different, i.e., the standard generic relay will have pin 30 where BMW wants pin 85, or something along those lines.]

melloh · « **Reply #23 on:** September 25, 2006, 04:51:23 AM »

Hello, gents. The actual test was done w/ the same (orange) relay as the lowbeam, not the generic tyco (because the orange relay has a tiny hole in the pins that I used to thread in a wire so I could test w/ multimeter as seen in the picture whereas the generic had no holes... so orange, regualr lowbeam relay was used for the testing situation 2).

Another note: I'm an idiot... ignore the part about fog no longer working. I did the test during daytime and neglected to notice i left the highbeams on after running voltage tests (did HB test last). So basically - nothing has changed. W/ orange or generic, no switch - fog on. w/ new 'real fog' relay (PN....631) - fogs off no matter what.

Someone before asked what color the wires were at the plug for the switch? It looked like they are both blue, just one has a white stripe in it (?). It can be seen in the link before:

Regarding continuity at the plug for the fog - is this an issue if we know the fogs can turn on? I can probably check it pretty easily, but i'm not sure it's necessary? This test would make sense to me only if the fogs wouldnt turn on no matter what. Or, am I missing something in this logic? Not trying to be argumentative or ungrateful - just trying to understand.

I know I say thanks every time... but, it's because I really cannot thank you gents enough for taking the time!

Cheers,

Henry

ak96ss · « **Reply #24 on:** September 25, 2006, 11:21:36 AM »

The wires at the switch should be gray and gray with a blue stripe.

The ground check is to make sure that the foglights are properly grounded - sometimes a bad ground can manifest itself strangely, as the current finds ground in new and interesting ways.

My relay is stamped Bosch part number 61 31 1 375 474... which adds to the confusion, as Pelican Parts lists a different part than either this one or the one you are using (61 36 1 378 238), and RealOEM is not very helpful in finding the appropriate relay. If it helps any, though, my foglights work AND this is the same relay as nearly all of the other relays under my hood.

I still think it's a relay problem. Do you have the Electrical schematic for the foglights, pages 6312-0 and 6312-1?