Main Beam

[Greeners]

morning

Picked up the car yesterday, didn't really have time to check and try everything out, but it would appear that the main beam won't come on when the indicator stalk is pulled back.

I assume that there will be a fuse and relay, but anything else that it may be before I start investigating?

Thanks

[Keith]

No fuse or Relay iirc but I have not double checked, High Beam is controlled by the LSM

So it will be the stalk switch itself or the LSM not cheap did you buy from a dealer?

[Greeners]

Privately.................suspect it's going to be a dealer vist or try and get a stalk off ebay

[Keith]

You need to fault find it properly really don't just assume stalk, it could be that or the LSM or the rotary coupler or the wiring.

Get a Haynes manual I think the wiring diagrams are just about useable.
you should be able to fault find from the stalk to the LSM quite easily.

I will double check tomorrow and see if there are any relays involved.

[Greeners]

You need to fault find it properly really don't just assume stalk, it could be that or the LSM or the rotary coupler or the wiring.

Get a Haynes manual I think the wiring diagrams are just about useable.
you should be able to fault find from the stalk to the LSM quite easily.

I will double check tomorrow and see if there are any relays involved.


Keith

Thanks for that...........I was making an assumption that as the "pass" facility worked, it's more likely to be the contacts in the stalk rather then the LSM.

Anything you can chip in would be much appreciated.

[Keith]

Ah so the flash works! in that case it may well be the stalk if this is true :-

The headlamp flash and dip / main beam switch is a three position non-latching switch which completes earth paths from the LSM via resistors in the switch. The switch is in the off position when at rest. Pulling the stalk towards the steering wheel will trip one of two switches.

The first switch operates the main beam headlamp flash. The switch completes an earth path through a resistor and the LSM recognises the resistance value as a request to activate the headlamp flash. The headlamps will remain illuminated until the switch is released. The second switch toggles the headlamps between dip and main beam.

The switch again completes an earth path through a resistor and the LSM recognises the resistance value as a request to activate or deactivate the main beam headlamps.

If you have a meter you can easily remove the stalk and test it. I have a spare one here from my 260.

At rest between pins 2 and 3 it is open circuit, in the first position it measure 1.2 K ohms in the second position it measures 300 ohms.

hth

[Greeners]

First chance I've had to have a crack at clearing the fault. Checked all the common points but everything pointed to either the LSM or switch.

Figured start at the switch and work back, bearing in mind it was only one funtion out of 3 not working.

Very easy to get off and dismantled it by removing the four screws in the bottom cover. I was half expecting to have a large number of springs and contacts fly out but instead I was greated with a very simple set of nylon "slides" and contacts.

After a number of trial and error reassemblies, I discovered the fault. I would suspect that the "sprung" part of the contact had simply moved by a fraction resulting in a lack of switching, Cleaned it all and popped it back an hay presto, I have main beam.

One minor point, is that the plug should only fit in one way, but mine appears to be a bit mis-shapen allowing it to fit in 2 positions.

A big thanks to everyone who chipped in some pointers :bowdown: :bowdown: :bowdown: , just wish I'd taken a photo or two for future reference.