Z3 headlight switch. Fixable?

[Duncodin]

Internally the headlight switch apparently has seperate contacts for left and right sidelights.

My switch very occasionally fails to switch on the right hand sidelights. I don't drive it often at night but noticed it while checking the lights. Switch off and back on and it works.

Was wondering if the switch is repairable? Take it out and clean or bit of contact spray?

I'd replace it but knowing my luck I'd just end up buying a bad one. The problem happens so very rarely that a breaker/seller likely wouldn't even know their's was faulty.

Or what's a new one cost? I'd ring dealer and ask but it's sunday.

 

[Ian&Sue]

Internally the headlight switch apparently has seperate contacts for left and right sidelights.

My switch very occasionally fails to switch on the right hand sidelights. I don't drive it often at night but noticed it while checking the lights. Switch off and back on and it works.

Was wondering if the switch is repairable? Take it out and clean or bit of contact spray?

I'd replace it but knowing my luck I'd just end up buying a bad one. The problem happens so very rarely that a breaker/seller likely wouldn't even know their's was faulty.

Or what's a new one cost? I'd ring dealer and ask but it's sunday.

From memory a new Headlamp switch is £140 odd quid.

 

[Duncodin]

From memory a new Headlamp switch is £140 odd quid.

You're right. Sytnerstevenage's site shows it as £158

 

[Ian&Sue]

You're right. Sytnerstevenage's site shows it as £158

But I'm not even 100% sure which one I need.

View attachment 309963

...508 is what I would expect. My car has fog lights.

...506 is for Scandinavia - where their cars have dip beam on at all times during the day.

Weird thing is my switch has a sticker with the ...506 part number on it so I'd be inclined to replace with that one. My car was around 5 years old when I bought it so I'd not expect anyone to have bodged about and fitted wrong one? Or what?

Again this is just from memory (so probably not very reliable) but I think 508 was the one that we got. Still haven't completely recovered from the shock of the price.

 

[Pingu]

You can dismantle all switches, but it will be full of levers and springs. Have a go if you are committed to a new switch and can delay the purchase.

If it all goes wrong, just buy a new switch (or a second hand one).

You may regret buying a second hand one, as they all deteriorate over time, but I'd risk it for around £30. The usual point of failure is the dimmer coil.

 

[Pingu]

You're right. Sytnerstevenage's site shows it as £158

Look at the bracketting in the description

The standard light switch is 508.

With foglight 506.

Scandanavia 507.

 

[Ian&Sue]

Look at the bracketting in the description

The standard light switch is 508.

With foglight 506.

Scandanavia 507.

Pingu is correct 506 is the one for car with foglamps & the one that we got. My memory fails again as predicted.

 

[Duncodin]

Again this is just from memory (so probably not very reliable) but I think 508 was the one that we got. Still haven't completely recovered from the shock of the price.

I was looking at the realoem page and reading the red bracketing wrong. 506 is the correct one.

 

[Duncodin]

You can dismantle all switches, but it will be full of levers and springs. Have a go if you are committed to a new switch and can delay the purchase.

If it all goes wrong, just buy a new switch (or a second hand one).

You may regret buying a second hand one, as they all deteriorate over time, but I'd risk it for around £30. The usual point of failure is the dimmer coil.

everyone seems to be complaining about the dimmer reostat. Mine works fine. I'm not sure I'd risk 30 quid or so to end up buying somebody's reject on bay.

The only problem with mine is that the right sidelights sometimes don't come on. The wiring diagram does show two switches inside - separate output for left and right. One of them is obviously dicky. Last MOT the tester told me that he'd changed a bulb. I'm sure the bulb was OK and that he'd just replaced the bulb and when he switched the light on it worked. I didn't tell him about the switch.

As you know I'm doing a rebody so I suppose I could just bring a wire across from the left side. then I wouldn't be relying on that dicky switch

 

[Pingu]

Reverse engineering the switch to delete the original and replace with something else is not for the faint-hearted.

Unless you want to take on a major electrical project, you will need the Z3 switch

 

[AirOps]

I think checking and cleaning the grounding points/wires may be a good way to eliminate a possible point of weakness in the circuit.

 

[Pond]

As you know I'm doing a rebody so I suppose I could just bring a wire across from the left side. then I wouldn't be relying on that dicky switch

As @Pingu says above, messing with the standard light switch wiring is not easy. It is connected, in one form or another, to almost everything on the car. More of a 'module' than a switch IMO.

 

[Duncodin]

As @Pingu says above, messing with the standard light switch wiring is not easy. It is connected, in one form or another, to almost everything on the car. More of a 'module' than a switch IMO.

I didn't mean changing anything on the switch. I meant that, for example, in the boot I could bring a wire from the left light cluster over to the right to power the right tail light. The same under the bonnet for the right side light.

Inside the switch the left and right sidelights are on different circuits probably to allow for separate left and right parking lights. The RH circuit in my switch appears to be intermitent.

Probably through lack of use.

Squirted a drop of points cleaner down the shaft. Then spent a few minutes pulling the switch (no not a euphamism)

Maybe it'll be ok. We'll see.

 

[Pingu]

I didn't mean changing anything on the switch. I meant that, for example, in the boot I could bring a wire from the left light cluster over to the right to power the right tail light. The same under the bonnet for the right side light.

Inside the switch the left and right sidelights are on different circuits probably to allow for separate left and right parking lights. The RH circuit in my switch appears to be intermitent.

Probably through lack of use.

Squirted a drop of points cleaner down the shaft. Then spent a few minutes pulling the switch (no not a euphamism)

Maybe it'll be ok. We'll see.

You are going to open a can of electrical worms if you attempt any of this without consulting your wiring diagram.

There are six independent output circuits and four independently fused inputs controlled by the light switch (and that is excluding the illumination light if fitted.

If you do what you are thinking, you will be joining some of these partitioned circuits.

 

[motco]

I didn't mean changing anything on the switch. I meant that, for example, in the boot I could bring a wire from the left light cluster over to the right to power the right tail light. The same under the bonnet for the right side light.

Inside the switch the left and right sidelights are on different circuits probably to allow for separate left and right parking lights. The RH circuit in my switch appears to be intermitent.

Probably through lack of use.

Squirted a drop of points cleaner down the shaft. Then spent a few minutes pulling the switch (no not a euphamism)

Maybe it'll be ok. We'll see.

That's where I would start. Plenty of contact cleaner - probably one with lubricant. If I recall correctly, there is a chip inside the headlight switch that duplicates the total mileage figure stored in the coding plug in the instrument cluster. It could easily be an urban myth, however.

 

[Duncodin]

You are going to open a can of electrical worms if you attempt any of this without consulting your wiring diagram
. . .
. . .

I'm able to read a circuit diagram so know my idea is viable. Seems I'm just not good at explaing it.

But the switch may well be on its way out anyway so I could be just kicking the can down the road.

So if my contact cleaning oil doesn't help I'm more likely to just replace the switch with a new one.

Although one day I might be ditching the switch anyway when I ditch the whole dash in my ReBody.

 

[Duncodin]

. . .
. . .
If I recall correctly, there is a chip inside the headlight switch that duplicates the total mileage figure stored in the coding plug in the instrument cluster. It could easily be an urban myth, however.

I think you're right about the urban myth.

Although the milage does appear to be stored in more than one place ie in the ecu

 

[Pingu]

I think you're right about the urban myth.

Although the milage does appear to be stored in more than one place ie in the ecu

That is an E46 thing, not an E36 thing. The E36 light switch only controls lighting.

 

[Pingu]

I'm able to read a circuit diagram so know my idea is viable.

6314.0-00 "indicates" you may be mistaken

 

[Duncodin]

6314.0-00 "indicates" you may be mistaken

I don't see the mistake?

In my light switch the internal switch (circled below) is (was) intermittent.

So. I was thinking of cutting the wire in the boot (Red X in the diagram) and joining (Red Line) from the left side so both rear tail lights are supplied by the same wire. That's basically how the brake lights are wired anyway. The only reason the tail lights have different circuits is to allow parking lights. I don't use Parking Lights so supplying both 5W tail lights from the same supply won't be a problem.

But now I've sprayed tons of wotsit into the switch and left it a day to drain and put it back together and it appears to work. Time will tell.