E46 saloon left rear fog light

[to3m]

My car said a rear light had gone, so I had a look and sure enough it had only one rear fog light (driver's side) and one rear number plate light. So I changed the number plate light first, as they're easier to get to... and the warning went away. Still no left hand fog light though!

The relevant light unit does have 2 bulbs in it, but only the lower one (which appears not to be the fog light) ever lights up, no matter what I do. I swapped the bulbs round and got the same result, so clearly both bulbs still work. The unit itself looked fine, with no burned-out connectors or anything (I've already had that problem on the main rear light cluster).

Is it supposed to be like this? Car is a facelift 330d saloon.

I always assumed there was one rear fog light for each side, but I don't think I've ever checked, and I'm getting conflicting reports from my googling...

[andyiley]

Under normal circumstances if a manufacturer just fits one fog lamp to the rear it is always the offside one.

Don't know if yours should have one or 2, but if the lights & fog lights are turned on & there is no bulb warning it is probably correct.

You could try the obvious & remove the good bulb & see if the bulb warning comes on.

[4rephill]

There's only one rear fog-light on the E46 on the off-side (The thinking is that by only having one rear fog-light there's less chance of the fog-lights being confused for brake-lights).

The near-side light assembly can be modified to to make the fog-light operational, but for the number of times that you use them, it's simply not worth the effort.

[to3m]

I've noticed many cars have only one rear fog light, and I'd have thought no more of it had there been just a blank space in the light fitting. But there's a working bulb there! If it's just there as a spare... very odd. I suppose it must have been cheaper to manufacture that way! I wonder how much by?

If I get a moment I'll try taking the spare out and seeing if any lights come on.

Edited by to3m on Tuesday 16th December 00:07

[4rephill]

to3m said:

I've noticed many cars have only one rear fog light, and I'd have thought no more of it had there been just a blank space in the light fitting. But there's a working bulb there! If it's just there as a spare... very odd. I suppose it must have been cheaper to manufacture that way! I wonder how much by?

If I get a moment I'll try taking the spare out and seeing if any lights come on.

Edited by to3m on Tuesday 16th December 00:07

Have you owned the car from new or was it bought second hand?

The reason for asking is that if you're not the first owner then it could be that a previous thought there was a bulb missing and so put a bulb in hoping that would get the lamp working and just left it in there.

(The bulb holder itself will be there but the metal connectors built into the lamp for the bulb will not be there. It's how BMW have done it since the days of the E36).

[to3m]

While at my parents' over Xmas I had a look at their E46 touring, and it only has one fog light come on as well. (I didn't look inside the housing, so I don't know if they've got two bulbs.) So I'm assuming that's just how it's supposed to be.

4rephill said:

(The bulb holder itself will be there but the metal connectors built into the lamp for the bulb will not be there. It's how BMW have done it since the days of the E36).

The metal connectors appeared to be there. It's possible they are non-functional - erm, OK, they *are* non-functional - I guess I mean that it's possible they're supposed to be like that - but overall the fitting for the bulb that doesn't light up looked very much like the fitting for the bulb that did.

[4rephill]

to3m said:

The metal connectors appeared to be there. It's possible they are non-functional - erm, OK, they *are* non-functional - I guess I mean that it's possible they're supposed to be like that - but overall the fitting for the bulb that doesn't light up looked very much like the fitting for the bulb that did.

Doing a bit of research, on the pre-facelift cars, the actual bulb holder was a blank plate so you couldn't fit a bulb, but on post-facelift cars the light unit had the bulb holder but was not activated on the light control module (apparently it requires some recoding to activate the the non-functioning bulb).

On the E36 and pre-facelift E46, all that was required was a left side (as you look at the car from the rear) light unit, and some cable to link to the offside fog light bulb wiring. I would have thought you could also get the post-facelift nearside fog light working by wiring it to the offside fog light (however, the light control module might throw up an error due to the higher loading being detected).

As I've already posted, for the number of times you use the rear fog lights, and the fact that the single fog light does the job just fine on its own, I don't think it's really worth all of the effort.

[helix402]

I have two rear fogs on my E46. It's a pre facelift with facelift rear lights and LCM coded to car+retrofit loom.

[4rephill]

helix402 said:

I have two rear fogs on my E46. It's a pre facelift with facelift rear lights and LCM coded to car+retrofit loom.

Nice job!

As I posted, it can be done, it's just whether it's really worth it to the owner.

I looked into modifying My E36 a few years back but then figured as I'd only used the rear fog lights about 5 times in 8 years of owning the car it just wasn't really worth doing.