Light Switch intermittent

[Gatsoburner]

Advise please if you would.

My cars got a dodgy switch on the headlight silver pull out dimmer. The lights come on fine pulling outward, just the twist, Its very touchy as when I turn it right the dash lights go off and on randomly until i ger it just right, not a smooth transition from very dim to bright as can be.

Anyone and idea why this is happening and what's the fix..

Cheers.

 

[Nodzed]

New switch is the best course of action, the wire rheostat is failing, there have been instances of the switches over heating and burning smells coming from them. If you search on here you will find quite a bit of info.

Headlight Switch - Be warned.

Ok well yesterday I had this very dry almost scraping noise from my headlight switch when adjusting the brightness of the dash lights as they were off then on then off again. Decided to take a look this evening when I had a chance as it's a known issue for overheating and catching fire. I have...

www.zroadster.org

 

[Gatsoburner]

Okeydoke, cheers

 

[ChrisD]

Advise please if you would.

My cars got a dodgy switch on the headlight silver pull out dimmer. The lights come on fine pulling outward, just the twist, Its very touchy as when I turn it right the dash lights go off and on randomly until i ger it just right, not a smooth transition from very dim to bright as can be.

Anyone and idea why this is happening and what's the fix..

Cheers.

Mine operates similarly.
Short term, possibly ineffective, fix is to liberally spray the switch internals with contact cleaner. Better solution is to just replace the switch. The third option that I take is to find a rotary position that works ok and then leave it - not turn the switch.
There are scare stories about fires caused by this switch. If you keep twisting it when it is intermittently working like this then that increases this potential risk.

 

[Gatsoburner]

I'm happy with it set but sometimes as I pull it out it turns very slightly then I need to start setting it be illuminated.

The cars only got 17k on the clock, how do these become unreliable, I'm guessing the materials degrade on time rather than use.

I've just looked on ebay, a few on there 50 to 130 quid but obviously 2nd hand. I assume the silver coil needs to inside the white casing to work correctly, anything outside is faulty?

 

[ChrisD]

I'm happy with it set but sometimes as I pull it out it turns very slightly then I need to start setting it be illuminated.

The cars only got 17k on the clock, how do these become unreliable, I'm guessing the materials degrade on time rather than use.

I've just looked on ebay, a few on there 50 to 130 quid but obviously 2nd hand. I assume the silver coil needs to inside the white casing to work correctly, anything outside is faulty?

I’d be a bit concerned about the overheating risk if it’s that intermittent. I’d also look at new prices as any used unit might have the same problem or be very close to it.
As you can imagine, miles have no effect on the durability of the switch. The materials degrade over time and with operations of the rotary function. I’d suspect heavy handed previous owners but since I’ve had mine from new I only have myself to blame. 35k miles but 28 years - well past the design lifetime of the switch.

 

[Nodzed]

I'm happy with it set but sometimes as I pull it out it turns very slightly then I need to start setting it be illuminated.

The cars only got 17k on the clock, how do these become unreliable, I'm guessing the materials degrade on time rather than use.

I've just looked on ebay, a few on there 50 to 130 quid but obviously 2nd hand. I assume the silver coil needs to inside the white casing to work correctly, anything outside is faulty?

The dimmer operation will be the rheostat coil, other than that I'm not aware of other issues with the switches. Be careful with buying 2nd hand that you don't end up with the same issue with the replacement.

@spurs fan in a coupe may be able to supply a decent replacement, he may pop on to advise if he sees this (maybe PM him)

The last new one I bought from BMW was £130 but that was about 4 years ago.

 

[Gatsoburner]

Yes, agree re 2nd hand, unlikely to get one that way especially if they're still available new.
Ill take it apart and see what's what.

Pretty impressed with BMW to be fair, still knocking out Z3 new parts, appreciate some are from newer model BMW cars but still settles the mind.

Snow here is getting in the way of doing jobs, too cold for knob twiddling which will please the wife..

Thank you Gents, gold dust advice

 

[Gatsoburner]

Bit the bullet and went outside. Only showing minus 1 so cracked on.

Took the unit out which was reasonably easy. Saw all the obligatory white dust which once the unit was out i blew away.

Closer examination found the units coils to be in really good condition. Took the unit apart, cleaned and sprayed then dosed with ACF50, polished up the contact dial and 'Bob is my Uncle'.

Turns very smoothly, no scraping noise and illuminates all through the turn from nothing to bright. Tried to add a video but too large, try again later.

Well chuffed. Mega thanks to you all, gave me the confidence to go and tackle it

 

[ChrisD]

Bit the bullet and went outside. Only showing minus 1 so cracked on.

Took the unit out which was reasonably easy. Saw all the obligatory white dust which once the unit was out i blew away.

Closer examination found the units coils to be in really good condition. Took the unit apart, cleaned and sprayed then dosed with ACF50, polished up the contact dial and 'Bob is my Uncle'.

Turns very smoothly, no scraping noise and illuminates all through the turn from nothing to bright. Tried to add a video but too large, try again later.

Well chuffed. Mega thanks to you all, gave me the confidence to go and tackle it View attachment 354775

Well done!
I may have a go at mine following your success.

 

[Nodzed]

Bit the bullet and went outside. Only showing minus 1 so cracked on.

Took the unit out which was reasonably easy. Saw all the obligatory white dust which once the unit was out i blew away.

Closer examination found the units coils to be in really good condition. Took the unit apart, cleaned and sprayed then dosed with ACF50, polished up the contact dial and 'Bob is my Uncle'.

Turns very smoothly, no scraping noise and illuminates all through the turn from nothing to bright. Tried to add a video but too large, try again later.

Well chuffed. Mega thanks to you all, gave me the confidence to go and tackle it View attachment 354775

Good save

 

[Gatsoburner]

Honestly well worth it. If I can do it anyone can !

Dont forget the small screw above and BEHIND the light switch, only thing I missed for about 10 minutes .
Other to bare in mind, the illuminated light icon might drop out. To replace it once finished do it Without the bulb in its holder, then put in the curved holder/bulb receptical, then lastly plug in the bulb.

 

[ChrisD]

I had a go at mine today.
The only problem I had was releasing the headlight switch from the vent housing. Luckily I was able to release it by just pressing in one of the side retaining lugs.

I don’t think I have the dexterity required to press in both lugs and pull the switch at the same time.
There was plenty of the white dust that causes the problem.

I was able to blow it out and clean up with contact cleaner without having the take the switch apart. There’s enough access at the back of the switch to clean up all of the rheostat.
All working smoothly now.
I just need to find a replacement for the indicator bulb.

I’ll try to find a suitable LED - I don’t want to have to get into this again any time soon.

 

[Pond]

I checked mine thoroughly before re-installing in the car, as my light switch housing is now glued to the rear of the dash. So any maintenance will require the entire dash to come out. Not something I want to ever do again TBH.

 

[Gatsoburner]

I had a go at mine today.
The only problem I had was releasing the headlight switch from the vent housing. Luckily I was able to release it by just pressing in one of the side retaining lugs.
View attachment 354887
I don’t think I have the dexterity required to press in both lugs and pull the switch at the same time.
There was plenty of the white dust that causes the problem.
View attachment 354889
I was able to blow it out and clean up with contact cleaner without having the take the switch apart. There’s enough access at the back of the switch to clean up all of the rheostat.
All working smoothly now.
I just need to find a replacement for the indicator bulb.
View attachment 354891
I’ll try to find a suitable LED - I don’t want to have to get into this again any time soon.

Superb. Quite easy to do once you get to grips with it. Good effort