Headlight switch replacement.

[RMF]

Hi all,

I had to have my 318ti jump started this morning as it hadn't been run for 2 or 3 months as it needed repairs.

Long story short, after having the car jump started I took it for a drive to recharge the battery. I happened to be driving through a tunnel when I noticed that all of the lights on my dash went out. The rear lights also no longer work, although my brake lights do, and the interior lights around the electric window and sunroof no longer illuminate either.

Anyway, I have researched this online and understand that it's likely to be the headlight switch assembly that's at fault. My question is, how easy is this to replace? I haven't been able to locate any tutorials on how it's done so any advice would be very welcome.

Thanks in advance.

[cooljess76]

No worries man, yes the headlight switch can cause the tails to not work. There's a rheostat(looks like a spring out of a mechanical writing pen that is bent into a "U" shape located inside of the switch) that typically blows when any of the wires related to the dimmer circuit shorts out. This most commonly happens when people replace the factory radio, HVAC panel, cigarette lighter housing or window switches. All of these things are tied into the dimmer circuit along with the instrument cluster lighting. If you've done any work on any of those things mentioned recently, then you'll want to go back and make sure the the wires are connected properly and not shorting out. Otherwise when you repair or replace the switch, the rheostat will blow instantaneously when you reinstall it. If the headlight switch itself shorts out(the bottom of the switch housing is metal) on something grounded, it will blow a fuse which will cause the tail lights not to work and I believe the driver side tail light will remain lit when the lights are switched off.

To remove the switch, you're going to have to remove the instrument cluster bezel(outer trim ring). You may not have to remove it completely, just slide it out of the dash and let it rest on the steering column.

To do this, you'll need to remove the head light and fog light switch knobs. Just unthread them and toss them to the side. Once the knobs are removed, take a flat screwdriver and pry off the small plastic plates behind the knobs. These are the triangular plates on each side of the instrument cluster bezel. Behind each of these plates, you'll see a screw. Remove the screws.

There's also two screws under the top of the bezel that need to be removed. After the top screws are removed, you'll need to unclip the bezel from the instrument cluster. There's two plastic clips on the bottom of the bezel holding it onto the cluster. Simply push down on the bottom of the bezel and pull it away from the instrument cluster.

*Tip* You may find it easier to manuever the bezel out of the dash and gain more access by placing the key in the ignition and turning the steering wheel slightly to one side.

So once the cluster and bezel are separated and the bezel is pulled out of the dash and resting on the steering column, you should be able to see the headlight switch. First, you'll need to unclip the electrical connector from the outward side of the switch.

Next you'll need to locate the two plastic clips on the cylindrical part of the switch that slides and clips into the instrument cluster bezel. There's on clip on each side of the cylindrical part of the switch that needs to be pressed inward to allow the switch to slide out of the backside of the instrument cluster bezel.

Once the switch is removed, you can either replace it(but make sure that the short in the dimmer circuit has been fixed otherwise you'll ruin the new switch), or if you're good at soldering and have access to a fine tipped soldering iron, you can attemt to repair it.

To repair it, start by carefully prying off the plastic cover away from the metal backing. This will give you limited access to the rheostat. Look very closely at the rheostat spring and locate the break. On the few that I've repaired, it's usually towards one end of the spring.

The spring is recessed in what looks like a white ceramic or plastic block. Using a fine-tipped soldering iron, very carefully solder the break. Pay special attention to the surrounding areas as to not accidentally melt them with the soldering iron. Once you're confident that the solder joint has successfully restored the connection, you can test continuity through the rheostat with a multimeter.

Before you reassemble the switch, inspect the circuit board for electrical shorts and burns. Inspect the rest of the switch to ensure that nothing was accidentally melted during your soldering job. Reassemble the switch by snapping it back together.

Reinstall the switch by clipping it into the instrument cluster bezel. Reconnect the elecrtical connector.

At this point you can test the switch but be extremely careful not to let the metal backing of the switch come in contact with anything metal inside of the dash. I think mine touched the anchor nut that the bezel screws into and blew the fuse.

If it tests fine, turn the lights off and remove the key from the ignition. Complete reinstallation by reinstalling the instrument cluster into the dash, replacing the triangular face plates and headlight/foglight knobs.

Hope that helps, good luck!

[RMF]

Hi Cooljess,

Many thanks for your response. Very detailed and clear. I'm absolutely hopeless when it comes to soldering though so I had already went ahead and ordered a new switch which I should receive tomorrow.

With regards to the removal of the switch that's in there. I have already removed both screw on knobs for the light switch and the hi/low beam switch and the 2 torx screws behind each of the small panels. There are also 2 torx screws as you mentioned at the top of the console, I also removed those but I wasn't able to pull the console out. It was dark though so maybe I've missed something as I was trying to do it under torchlight so I'll have another look at it tomorrow in the daylight before work. I'll let you know how I get on.

Thanks again.

EDIT:

Oh one more thing. No electrical work has been done on the car at all. Is it possible for these things to blow on their own? When it did blow I was trying to adjust the dimmer switch as I was in a tunnel, and it was at that time the lights went out while I was adjusting the switch itself.

[cooljess76]

Cool. It's been so long since I've removed mine, I may have missed one or two details. I just looked at mine and the upper screws do in fact have to be removed and the bezel has to be separated from the instrument cluster. The bezel clips onto the instrument cluster. After the two upper screws are removed, push downward on the bottom of the bezel. There's two clips holding it onto the instrument cluster. Once these lower clips are disengaged, the bezel should detach from the instrument cluster. Leave the instrument cluster inside of the dash, and slide the bezel out and onto the steering column. Sorry about the confusion. BTW, by "bezel" I mean the plastic trim ring that surrounds the instrument cluster.

[RMF]

Thanks cooljess. You're definitely right. The bezel is loose at the top but firm at the bottom. When it's light I'll probably be able to see the clips that are holding the bottom of the bezel on. I've removed the underside of the dashboard aswell in the drivers side footwell under the switch so I can see up into there. Do I have to access the clips from down there?

[cooljess76]

Originally Posted by RMF

Thanks cooljess. You're definitely right. The bezel is loose at the top but firm at the bottom. When it's light I'll probably be able to see the clips that are holding the bottom of the bezel on. I've removed the underside of the dashboard aswell in the drivers side footwell under the switch so I can see up into there. Do I have to access the clips from down there?

You can't see them because they kinda "hook" under the bottom of the cluster. You don't need to see them though, just push downward on the lower part of the bezel where it meets the clear plastic shield on the instrument cluster. You should feel it release.

[RMF]

OK, I got it out of there this morning. It was pretty easy in the end although unplugging the electrical plug from it was tough as it was very tight. While trying to remove it the plug seperated on one side and I'm not sure but I think it may have broken a couple of wires on the inside. So this is going from bad to worse, but I'm not sure. Maybe it'll be OK.

EDIT:

I just received the part but it seems the wrong one. This one has 2 clicks when pulling out so it may be for a car with fog lights. Also, the metal stem that the knob screws onto seems to be thicker, so I don't think that my silver one will fit but I may be wrong about that. Also, this part has an extra digit on the end.

Part number 613183535089

Maybe it's from a Z3. Anyway, I'll try it out when I get home from work.

[RMF]

OK I just put the new switch in and the symptoms are exactly the same. It looks like an old beat up part though so I guess it's possible that it's blown as well. The part number was also the exact same as the one that we had in there previously.

Could this be caused by anything else? Blown fuses that sort of thing?

[cooljess76]

Like I said before, you have to locate and fix whatever shorted it out in the first place. If you haven't done that, there's a good chance that you've blown the new switch. Have you recently removed or replaced the stereo, HVAC panel, window/sunroof switches, door lock switch, cigarette lighter or anything in one of those areas?

[RMF]

Originally Posted by cooljess76

Like I said before, you have to locate and fix whatever shorted it out in the first place. If you haven't done that, there's a good chance that you've blown the new switch. Have you recently removed or replaced the stereo, HVAC panel, window/sunroof switches, door lock switch, cigarette lighter or anything in one of those areas?

Nothing at all has been removed or replaced. That's the problem.

[RMF]

It's fixed. I'm using the old switch and got it working simply by replacing fuse 37. I should have checked that to begin with but I was convinced that it was the switch from what I had read.

Anyway, big thanks to you Jess for taking the time to help me out with this.

[adamb]

I'm having this same issue for the most part part. Just started the other day. Cluster and instrument lights went out as did my right side parking lights but the actual use of my turn signals, and brake lights work just fine, so do my lows, highs and fogs. Fuse 37 keeps blowing as does a fuse for my angel eyes that is wired in with my alarm. I got the headlight switch out and took it apart cleaned it up tested it and I didn't see anything bad with it, however im not an electrical expert. I haven't performed any maintenance or changes on any components in months on the car. I tried isolating the brake light, cluster and turn indicator and still having the problem. Once i pull the switch to the first click, the fuse blows..

PLEASE HELP!!

[Alexxx]

I'm having the same issue on bmw 318ti e36 compact, I changed the window switch and the interior lights stopped working . I fix the rheostat, and now everything works perfectly.
1: remove steering wheel
2: remove instrument cluster
3: remove knob for lights and fog light
4: remove triangle cover at lights and fog lights
5: remove cover at dashbord
6: remove plug light switch
7: remove light switch and repair rheostat

[furutani]

Hello. The light on my 318ti also stopped working, and when I checked the switch, there was a short circuit at the base of the dimmer. Even if i solder it, the fuse will blow. The fuse blew some time after the audio was changed, so I don't think it has much to do with it. Is there anything else I should check? 　I translated it with Google, so I apologize if the English is incorrect.

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[furutani]

Originally Posted by furutani

Hello. The light on my 318ti also stopped working, and when I checked the switch, there was a short circuit at the base of the dimmer. Even if i solder it, the fuse will blow. The fuse blew some time after the audio was changed, so I don't think it has much to do with it. Is there anything else I should check? 　I translated it with Google, so I apologize if the English is incorrect.

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this

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