[Cloud9...68]

I still have several problems that need to get fixed before my two-year-long project finally comes to an end and I can actually drive my car again, but this is the one I feel most helpless about, because electrical issues are just not my forte. As it says in the title, the tail lights turn on, as they should, with or without the key in the ignition when I turn the headlight switch to the intermediate "driving light" position, but when I turn it fully clockwise to the "headlight on" position, the tail lights turn off. Also, the alarm that chimes when the key is in the ignition and the door is open stops chiming when the I turn the headlights on. Finally, the dash lights flicker briefly when the headlight switch is in the "driving light" position, but quickly turn off, and stay off when I turn the switch to turn on the headlights.



All the other lights that worked before I started the project still work (brake lights, other than the third brake lights, which stopped working a few months before I started the project, flashers, turn signals, dome light, red alarm LEDs in the door lock buttons, and reverse lights all work), so it must have something to do with the operation of the headlight switch. I did tap into a wire (can't remember which one - I can check if it helps with the troubleshooting) of the headlight switch that goes hot when the switch is turned to the "headlight on" position to activate a relay to send power to the low beam filament of my new Hella Bi-halogen fixed lights, which work perfectly on both low and high beam, but disconnecting this wire (at the relay, because it's much easier to disconnect from there) doesn't change my symptoms.



I've looked at the wiring diagram, but I can't make any sense out of it - I can't even match the wires going into the tail lights to their locations on the switch, to show you how adept I am at reading wiring diagrams. I did disconnect several electrical components during the project (removed the cruise control control module, the air bag control module, the windshield washer pump, the headlight motors, the sunroof drive components, and disconnected the power seat connectors. But I don't think any of this is the cause of my problem, because all the other lights work, and the little battery does an incredible job of cranking the engine, possibly aided by the hefty new Higher Connections power cables..



Should I try tapping into a different light switch wire to send power to the headlight low beam filaments? Any reason why it would make a difference which wire I tap into, as long as it goes hot when the light switch is on? Any other suggestions from the electrical whizzes (Flash and DaveN, I'm talking to you...) on this board? Thanks.



Edit: One new piece of info: If I rotate the headlight switch slowly, the dash lights come on and stay on when the switch is between the "off" and the "running light" positions, but turn off as I keep rotating toward the "running light" position. So the headlight switch seems to definitely be the source of my problem in some fashion. I wonder if I did something to it as I was tapping into the wire for the new headlights...

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[flash]

it sounds as simple as two wires being reversed at the switch

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[Cloud9...68]

[quote name='flash' timestamp='1366464910' post='141675']

it sounds as simple as two wires being reversed at the switch

[/quote]

I'll check, but I don't remember removing any of the wires at the switch. It has to be something with the switch, though, because all the symptoms occur as a direct result of turning it. That thing is no fun to get to, especially with my seat now bolted into place. I'll have to remove the steering wheel to improve access.

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[flash]

??? the headlight switch pops out very easily. yank off the knob, remove the nut, push it back through the dash, pull down. done



any chance though that this is connected to the multi-pin connector issue?

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[Cloud9...68]

Ah, thanks. I was doing it all from the back before. It was a real battle, so I suspect I buggered something up in the process. Plus, doing it the way you describe should give me good access to the connectors as I turn the switch, allowing me to test what's happening with a volt meter.



I highly doubt this is in any way connected to the multi-pin issue. I checked the final connections on that connector at least three times before finally buttoning it up, both against photos people had posted, and against the wiring diagram, and every other system on the car, as far as I can tell, is working. This tail light issue seems to be isolated to the headlight switch.

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[Cloud9...68]

Well, not so simple. The wire bundle going into the headlight switch is way too short to allow the switch to drop low enough that I can see, let alone manipulate, the wires. I turned myself into a pretzel and twisted into the 6" x 6" opening between the steering wheel and the seat to get under the dash to confirm the bundle isn't simply getting snagged on anything, and it isn't - it's just very short. So, I'm looking at removing the lower part of the dash - the gray-going-on-purple piece in the picture below the main black panel:



   



I've got the switch pulled down as low as it goes, and you can see it in the picture in front of the brake pedal. I couldn't find anything in the manual about how to remove this lower section, but I know several people here have removed their dashes, so I'm hoping somebody could give me some tips. I removed the two screws on the very side, near the door jamb, and I pulled back the center console, but it doesn't want to budge. Thanks.

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[flash]

probably easier to pull the cluster and pull it up through the top



the other choice is to remove the black dash piece. it comes out pretty easily. pop the triangular piece off, remove those screws, remove the screw at the bottom near the steering wheel that joins that pice to the next one, pop the little cover next to the vent off, remove those screws, and then gently lift it out. the switches just snap into place, but you can just unplug the wires.

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[Cloud9...68]

Thanks, Flash. I think the option to pull the black dash piece is the most viable, as I think the wire bundle is too short to allow for much access to the switch through the cluster. I'll give it a whirl.

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[JTP]

I did that a few months ago. Taking that black trim piece off takes about 5-10 minutes and the switch is very accessible there.

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[Cloud9...68]

Aaarrghh!!! I've removed all five visible screws holding this thing in place, and have disconnected the fog light switch and the dash light dimmer, but something still has a death grip on this piece, from the back, in the vicinity of the hole that the headlight switch occupies. The car is back up on jack stands, and the door is very close to some shelving, so I can't open it very far, forcing me to work in very tight confines, so it's hard to see very much. I did managed to take my life in my hands and crawl under the dash again (my ensuing rescue would have made for some funny stories down at the fire station), but I can't see anything that's holding this piece in. I had an easier time installing the firewall brace. What am I missing?

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[JTP]

If I recall correctly, I had to remove the triangular trim on the side of the dash, which gets covered when the door is shut. I think there are two screws that hold that dash trim on under that triangle. Once all the screws were out it had to be slid out at an angle too.



Wish I took pictures, it was about 6 months ago.

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[Cloud9...68]

I think you're right about having to pull at an angle. After a lot of grunting and some choice language, I got the thing to break free after pivoting it up and down while pulling, "break" being the operative word, because it sounded like something snapped on the inside part of it, but it doesn't look seriously damaged, and should be able to go back in and stay put.



But now that I have access to the light switch, I'm not sure how to go about troubleshooting my problem, since the switch is sealed, and the connectors are all inside. I could try to pry it apart, but I'm afraid I'll break it. I did go ahead and disconnect the tap wire from the wire (the yellow/blue one, which goes to connector 57K, according to the wiring diagram) I had connected it to, but as expected, this didn't have any impact on the symptoms - the tail lights still turn off as soon as I turn the switch to the fully on position.



As I said in an earlier post, I can't figure out which of the wires to the light switch activate the tail lights. Tapping into the yellow/blue wire is the only thing I did with this switch during this project. I find it had to believe the switch went bad just sitting for two years, but I suppose stranger things have happened. I really don't want to just replace the switch without doing any troubleshooting, as I imagine a replacement switch isn't cheap, even used.



In case anybody is wondering why I'm so concerned about the tail lights in a track car, it's because it won't pass inspection without functioning tail lights, which means I can't register it, which means I can drive it to the track. Not legally, anyway. So, getting this fixed is my highest priority at the moment.



Edit: I take it back - I just checked, and there are a couple of headlight switches on eBay for just $20, which would be a no-brainer if I was sure a new one would cure my problem. But also, one of the photos of one of the switches on eBay gives an indication as to how to take it apart, so I'll try that tomorrow and see if my voltmeter can produce any clues.

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[gbarrier]

Sometimes it's as simple as the switch just wearing out or coming apart inside. Doesn't hurt to have a spare at that price. My current 968 came with one and I'm hanging on to it. The <acronym title='previous owner'>PO</acronym> bought it while chasing a different wiring problem and one of the things that so frustrated him that he finally offered the car to me. I knew it was just a matter of time. His problem was that he could never get the tag light and dash lights to burn. That circuit always blew the fuse. Turns out that the guy before him while butchering up a radio install switched the plugs on the back of the mirror switch with another switch beside it on the console. Finally found it when cleaning up radio wiring and found that all worked well before I plugged up those switches. Luckily I still had my tip at that time and compared wiring. It's the little things.

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[Cloud9...68]

Yes, I agree. I should probably go ahead and order one of the switches on eBay, and have it as a spare if it doesn't turn out to be the problem. Like I said, seeing a few pictures of these switches taken apart shows me how they come apart (very simple, actually), so I should be able to do some quick troubleshooting of the connectors.



But first, I need to replace a leaking valve cover gasket on my daughter's 04 325i, so work on the 968 will have to wait until later in the day.

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[Cloud9...68]

OK, I took out the headlight switch, and ohmed every combination of connectors on it, but I can't make any sense out of what I saw relative to the wiring diagram. Here are the combinations of connectors that created a short, with the switch in the "off", "running light", and "headlight" positions:



"Off" position: No combination of connectors creates a short, as expected



"Running light" position: Connectors (57,L), (57,R), (57,30), (57,58), (R,30), (R,58), (R,L), (30,58), (30,L), (58,L). Nothing in combination with connectors 30b, 56, X, 56K, or 31



"Headlight on" position: Connectors (R,30), (R,58), (R,L), (30,58), (30,L), (58,L), (X,56K), (56K,56), (56,X). Nothing in combination with 57, 30b, or 31



The switch doesn't feel strange in any way - it moves crisply from position to position. Could somebody who understands wiring diagrams a whole lot better than I do please take a look and see if what I'm reading is indication of a correctly functioning switch or not? In particular, it would be very helpful to know which connector on the headlight switch is supposed to activate the tail lights. I don't mind buying a replacement switch, but I'd like to at least have some inkling that it's is the cause of my problems. Thanks.

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[Cloud9...68]

Well, lo and behold, magically, everything now works! I thought of something to test that I had overlooked - I wanted to see if the front running lights behave the same way as the tail lights (shutting off when the headlights are turned on), so I plugged the headlight switch back in, turned it to the "running lights" position, and immediately noticed that the dash lights were on. So, I turned it to the "headlights on" position, and the tail lights didn't turn off, nor did the running lights or the dash lights, and the headlights work. All I can think of is that there's something flaky in the switch, or with one of its connectors, and the act of unplugging it and plugging it back in undid whatever was out of kilter, even if only temporarily. I guess I should order a new switch while they are available so cheap. Anyway, this is a huge load off my mind. Now, to tackle the (no)-power steering...

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