Another mysterious lighting issue

[oldnbold]

Re my 318i cabrio. When the ignition is turned on with the light switch set to off, the left hand side parking lights come on (front and rear). Pulling the light switch to sidelight position, all is normal, all sidelights lit.

I've confirmed that the LHS lights are getting their feed from F22. Also, they come on even when the light switch is disconnected.

I can only guess there's a short in the wiring between F22 and the switch but that does seem unlikely. I've tried to open up C103 to do some checking of the wiring (as this connector is the halfway house between fuse and switch) but I can't work out how do so and I'm too chicken to use force!

Any wise words from a guru would be much appreciated! Thanks in advance.

[Brianmoooore]

Sounds like you've discovered the parking light function of the indicator switch to me!
What position is the indicator switch in?

[oldnbold]

Err - neutral Brian, I promise! And selecting left or right indicator with ignition on (and light switch not in place) has no effect on the bewildering left-side lights which remain stubbornly lit.

Can you help with C103? It looks simple, slide down what must be some sort of lock and prise off the plug but this won't budge and, as mentioned in my first post, I'm reluctant to use force. I'm not too impressed with BMW's plug designs, there seems to be no common design approach and no easy way to get a grip that doesn't involve stressing the wires.

[BenHar]

What happens if you take fuse 22 out?

Ben

[Brianmoooore]

C103 is parted by pulling out the slider while at the same time pulling the plug out. There's a sort of ramp on the sliding bit. This design is used a lot on later BMW models.
Been studying the wiring diagrams, and really can't see anything that could cause this - the wiring to the LH parking and tail lights is very simple. Just a wire to the front and on to the back, plus the connections to the indicator switch. Not even the complication of a lamp check module on yours.
A similar fault on the RH lights would have much more potential.

[oldnbold]

Thanks Ben. Yes, F22 is powering the lights (as it should) and if it is pulled when in the odd condition the LHS lights do indeed go out.

I've been trying to trace the wire runs and it seems that a group of three relays may be involved. These are physically on the electrical bracket behind the ABS box, next to C103. I can't find these relays on the various circuit diagrams and I've no idea what they do. Any ideas? Life would be much easier if the bracket could be removed, so giving better access to these connectors and relays. I'm going off BMW's electrics big time.

John

[Brianmoooore]

The three relays (two orange and one blue?) are for the dim dip headlamps and for the feature that allows the widows to be operated with a door open when the ignition is off. The orange relays are connected to the headlamp circuits, but not those for the parking lights.
There is a two pin plug and socket on grey/x wires, a few inches from the indicator switch, which is associated with the parking lights. Should be accessible by just removing the lower column shroud.
Try unplugging this and see if it affects the problem.

Going off now to sort out the electrics on a Massey Ferguson 250! Much simpler circuitry than an E30, but so much poorer quality.

[oldnbold]

Thanks very much Brian and I hope the M-F burst into thunderous life.

The relays are: green, white, orange but I don't suppose that makes much of a difference. Even with your guidance, I can't find these relays on any of the diagrams I have, further help would be appreciated if you have a moment. There's no real reason to suppose that they impact on my sidelight issue but the clearly overheated and partially fused together wires that I've mentioned go towards them so I can't help feeling suspicious.

I'll have another go at C103 and the two-pin plug/socket you mention tomorrow. Logic will prevail - maybe.

John

[Brianmoooore]

Few questions: Is this a UK spec., RH drive car?
What age?
Do your windows work with the ignition off?
Do they work with the ignition off and a front door open?
If you pull the main lighting switch to the first position, do both front parking lights, both tail lights, both registration plate lights and the interior panel lights all come on?
If you turn the ignition on with the lighting switch in the first position, do the dipped beam headlamps come on at half brightness, as well as all of the above?
If you push the indicator switch up or down as far as it will go with the ignition off, do the parking light and the tail light on the appropriate side come on, without the registration plate and interior panel lights?

M-F is finished, but going nowhere at the moment, since it's short of 30 litres of oil that Opie Oils (oilman on here) have failed to deliver on time!

[oldnbold]

Hi Brian,

Many thanks for the interest you are taking, it is very much appreciated.

I'm away from home at the moment and can't immediately answer all your queries. Some I can:

LHD, Canadian spec. Date of manufacture 1993. This means the dipped lights were originally always lit as DRLs but this was modified some time ago as the constant flashing from helpful cars became rather unwelcome.

Windows - will check. I don't think so, they only work intermittently under the best of circumstances.

Lighting switch in position 1 - yes.

In that condition, the dipped lights do not come on. And they never did, even with the original Canadian spec wiring for which the sequence was: position 0 - dipped headlights on; pos 1 - lights off and pos 2 of course lights on again. There was never a half brightness situation that I was aware of.

indicator switch - will check but as far as I recall it impacts only on the amber indicator lights.

As you will gather, the car is not typical!

I'll post again shortly with the missing info. And after I've (hopefully) opened up C103.

John

[oldnbold]

Hi Brian,

Well I've had another look at the beast. The asymmetric side lights turned out to be a bit of a nonsense. As wired, and this is because of the Canadian specification, the sidelights are on all the time the ignition is on. The reason the RHS lights were not on was simply that Fuse 23 was dud. I had missed this because to a visual check it was fine - not something I've experienced before. Anyway, a new fuse brought all the sidelights up when the ignition was turned on. Further checks established that power is fed to the lights when the light switch is fully in and that this is provided via fuse 8, which normally feeds just the rear screen demist blower. Pulling this fuse brings the lighting to UK normal. I had a go at finding out how this power is applied to the lighting circuit and confirmed that the three already suspect internal relays are indeed involved but pulling them killed the lights completely so it ain't simple. But pulling fuse 8 will get me through the MOT which is the first priority and may make the car saleable.

Thanks for the wise words, the help was much appreciated. I suppose the moral is don't buy Canadian spec E30s but the price was very good back in 1994!.