What goes up, must come down right? Headlight woes *FIXED*

[ian65]

Except if it's my headlights....... they go up and won't come down no matter what.......... any ideas?...... combi switch maybe?





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[KYPREO]

Firstly I'd be checking the headlight retractor switch next to the demister switch.

[myatt1972]

And your blood pressure

[Hobbawobba]

Firstly I'd be checking the headlight retractor switch next to the demister switch.

This has caught me out a few times before! Hahah. Forgot to plug it in once and drove around for a week wondering why they wouldn't go down

Only other thing I can think of right now would be the fusible link?

[KYPREO]

Yep, and the contacts on the headlight switch can carbon up too. From memory the power circuit for the headlight motors actually passes through the switch. If the headlight stalk on the combi switch is turned off, but the retractor switch thinks it is in the headlights up position, the headlights stay up. If both headlights refuse to go down, it is often because the retractor switch is always open/always closed (can't remember which way it goes lol). Check whether it is plugged in, then remove and test for continuity across the terminals. It can be take apart and cleaned, just like a power window switch.

Good idea on the fusible links too. Best to eliinate that as an issue, which is easily done.

[ian65]

thanks for the info and advice chaps... swapped out the retractor switch for another one but still no joy.... and fusible links are ok... the headlights won't raise at all if the link is blown... I suppose next stop is the combi switch

[codge]

Sorry, a bit late to this:
Looking at the Haynes Schematic 10.54 Sytem 'N' (I know it's Series 2 but S3 should be same).
Another possibility is that the 'down' circuit is broken either at a fusible link (checked & discounted), or on wire RY between the retractable switch and the motors 'down' circuit connections, I presume this is looped across between the two motors. Because the two headlights have failed together(?) it says not motors or diodes or other hardware in the headlights.
The combi might be part of the problem but suggest try this first:
Maybe install temporary flying links between 'RY' terminal X02 at the back of the retractor switch and 'RY' terminals E04 looped to E03 at the headlight motors. Disconnect battery, install temporary wiring, leaving existing in place, and reconnect to test.
'RY' code should be red wire with yellow stripe. EO3 and EO4 might be either way round depending which headlight loops on to the other.

Let us know how you're getting on.

[ian65]

Sorry, a bit late to this:
Looking at the Haynes Schematic 10.54 Sytem 'N' (I know it's Series 2 but S3 should be same).
Another possibility is that the 'down' circuit is broken either at a fusible link (checked & discounted), or on wire RY between the retractable switch and the motors 'down' circuit connections, I presume this is looped across between the two motors. Because the two headlights have failed together(?) it says not motors or diodes or other hardware in the headlights.
The combi might be part of the problem but suggest try this first:
Maybe install temporary flying links between 'RY' terminal X02 at the back of the retractor switch and 'RY' terminals E04 looped to E03 at the headlight motors. Disconnect battery, install temporary wiring, leaving existing in place, and reconnect to test.
'RY' code should be red wire with yellow stripe. EO3 and EO4 might be either way round depending which headlight loops on to the other.

Let us know how you're getting on.

thanks Dave, you're right but posted this about an hour after I'd fixed it

What a bleedin' game this was....

first I checked the fusible link for the retractor just to be sure and although I I knew that the motors wouldn't operate at all if the link was blown, you sort of get to the point where you begin to doubt yourself with these kind of problems.
The link was ok so next I swapped out the headlight rocker switch for another one.... still no joy.

Next I pulled off the steering wheel, ignition cowling and combi switch.... got it on the bench, tested it, stripped it, cleaned the internal contacts, reassembled it, put it back on the car and.................................nothing

I then got out the mutlimeter and started methodically checking the lighting circuit. I had 12v at the rocker switch in the down position but not at the connector to the headlight motors. I did what Dave suggested and put a flying lead between the rocker switch and the motor connector 'down' circuit and still nothing happened. I then decided the break into the loom to test the conductivity of the retract wire and found the problem.

The pop up headlight motors only go in one direction, not reverse as many people think. There are two signal or trigger wires, a red wire triggers the 'up' and a red wire with a yellow stripe triggers the 'down'

When the lights are switched on via the combi switch or the headlight rocker switch is switched to 'on', the red wire goes to +12v, the red/yellow wire goes to 0v and the crank on the headlight motor rotates 1/2 a turn until the built in relay cuts the power.... at this point the lights are in the raised position.

When the combi switch or the rocker switch are turned to 'off' the red/yellow wire goes to +12v and the red wire to 0v and the motor then operates another 1/2 turn until the lights are down and the relay cuts the power.

The red/yellow 'down' wire runs with the rest of the loom from the dash, through the bulkhead, and then along the offside chassis rail to the front of the car where it turns and runs along the round tube in front of the radiator and then back along the nearside chassis rail. Halfway along the round chassis tube the red/yellow wire splits into 2.... one wire then doubles back to feed the o/s headlight motor and the other one continues on to feed the n/s headlight motor.

I unwrapped a section of loom just past the o/s suspension tower, found the red/yellow trigger wire and tested it at this point and found that it was showing the correct voltage here according to the switch position. The same wire at the motors was not showing any voltage though so there was obviously a break somewhere. As I didn't want to keep unwrapping the loom to find the break I got the soldering iron out and spliced a couple of wires into the red/yellow 'down' wire at this point and then ran this with the existing loom to the headlight motors.

This solved the problem and the lights now work fine again. I've had this problem with the headlights retracting for about a year but in the past they have gone back down of their own accord, sometimes a few minutes after I turned the lights off, sometimes a few hours..... this week though they just went up and stayed there.

I'm still a bit mystified why they didn't retract when I connected the flying lead up but who cares? They are ok now

I had a bit of a despairing moment though....when it was all back together and I drove it out of the garage I looked at the engine and saw loads of water on top of the inlet I put stainless core plugs in and rtv when I put the Elford inlet on so couldn't believe that they would leak but there was a load of water on the inlet. This would have taken the car off the road for the rest of this year because it's a major job to strip off the whole of the Elford setup to get to the core plugs / inlet manifold and I just haven't got the time ( or the inclination) to do that.
I then remembered that to get to the loom I'd had to remove the rad expansion bottle and I'd rested it out of the way on top of the engine...... hence the source of the water..... thank **** for that!

[codge]

Sorry mate, I keep thinking I could have at least saved you the steering wheel off / combi switch on the bench job.

Once on a previous car (Silver S3 also), we had a mini fire originating on that same circular cross tube in front of the rad......the wiring loom had been hit by a pebble. (Some considerable time earlier we think 'cos neither me nor Ellie could remember an impact).
It was actually a bit more than a mini fire 'cos Ellie had to jump out with smoke and all the chime alarms going off - it took out the front car power just about completely.

The car had to be towed home with only half the electrics working, then I spent about a week in the freezing cold by-passing sections of burnt-out loom.
So what do I say? Weather's turned out nice again?

[Hobbawobba]

Sweet. Good to hear you got it sorted quickly. Electrical problems can be so frustrating aye!