Attleborough, Norfolk
I did initially think it was mechanical. How does it compare to the other side?
Lights/loom issue PT3 strange stepper behaviour
- Thread starter bigwinn
- Start date
I think I need to get my hands on a like for like unit to see how the internal mech moves
Correct me if I'm wrong but the stepper motor has 4 wires going to it?
That leads me to think the motor has hall sensors inside to measure its travel. When it's out of the car and you turn on ignition it does its morning stretch to check the ends points. When it's in the headlight it can't do the morning stretch so shuts it down. I'd say there is something stopping the full movement inside the headlight.
That leads me to think the motor has hall sensors inside to measure its travel. When it's out of the car and you turn on ignition it does its morning stretch to check the ends points. When it's in the headlight it can't do the morning stretch so shuts it down. I'd say there is something stopping the full movement inside the headlight.
Is the up/down adjuster (the ones you twist, external to the headlights - I think a 5mm hex?) fully maxed out in its adjustment? From memory, it's the adjustment in the middle for up/down, the adjuster on the side of the headlight for left/right.
That might be causing the jamming if it's not got enough travel? There is a white clip/sleeve that rids along a long threaded rod that is used to adjust the aim up/down or left/right. I'd try turning the adjuster and seeing if that changes anything.
That might be causing the jamming if it's not got enough travel? There is a white clip/sleeve that rids along a long threaded rod that is used to adjust the aim up/down or left/right. I'd try turning the adjuster and seeing if that changes anything.
That’s a good shout
I’ve spotted that the adjustment before I started working on it was wayyyy out. That could be partly because it was held in with only 2 of the 4 headlight fixing screws… but could also be that it’s over adjusted
Steve and I just had a play with it
When the adjuster is plugged in and moved slightly off centre it cycled freely and happily 8 times.
Closer inspection shows that most of the wires are in a bad way so I am going to get it on the kitchen table for a closer look at the wires first… then I’ll look at travel and adjustment
Appreciated!
I’ll drop you a text budLet me know if you want my spare lights
A little closer to a solution I feel
I can rule out wiring. I’ve checked and cleaned, looked at continuity: still no change
I think the observations about light adjustment being the issue are more likely. I moved the adjusters around and the issue got worse
So in the am I’m going to move the adjusters to the point of least resistance to movement of the carrier and see what impact that has on the electric adjustment.
@Usel I think you are on the money with it being ‘computer says no’ if it can’t do the full test travel
Will report back
I can rule out wiring. I’ve checked and cleaned, looked at continuity: still no change
I think the observations about light adjustment being the issue are more likely. I moved the adjusters around and the issue got worse
So in the am I’m going to move the adjusters to the point of least resistance to movement of the carrier and see what impact that has on the electric adjustment.
@Usel I think you are on the money with it being ‘computer says no’ if it can’t do the full test travel
Will report back
Well that’s surprised me
I managed to fit and test a new headlamp unit
The issue still persists- so I was completely wrong thinking it was electrical or mechanical issues inside the lamp causing it (albeit the existing lamp is deffo shagged with failed mechanical adjusters
So back to the drawing board.
I’m going to run 4 new lines from the lcm to the lamp to rule out a loom issue
I managed to fit and test a new headlamp unit
The issue still persists- so I was completely wrong thinking it was electrical or mechanical issues inside the lamp causing it (albeit the existing lamp is deffo shagged with failed mechanical adjusters
So back to the drawing board.
I’m going to run 4 new lines from the lcm to the lamp to rule out a loom issue
Do you have another LCM you could try? Before you faff about rewiring.
Ah ok, noticed you'd tried that. So possibly a dodgy connection in the pins you worked on?
It’s very possible
The second lcm with the manual adjusters yields the same issue with the drivers side- no up/down movement whereas the passenger side does move
So you have definitely narrowed it down to that wiring between LCM and light then.
I suppose the replacement loom could have had an issue already?
Do a continuity test with a multimeter. I think you have a broken stepper motor?
If so cut the stepper off leaving the plug with lots of wire. Push the plug into the connector on the car and then connect a long wire to one of the 4 wires. Then take the other end of the long wire to the lcm so you can check there's not a break with a multimeter. Do the same for all 4 wires.
If so cut the stepper off leaving the plug with lots of wire. Push the plug into the connector on the car and then connect a long wire to one of the 4 wires. Then take the other end of the long wire to the lcm so you can check there's not a break with a multimeter. Do the same for all 4 wires.