Odd lighting fault

[itcaptainslow]

My 75 has decided it’s going to full on strop since having a daft amount of money spent respraying & rechroming it...

A bit of background-it’s a dry use only car, currently SORN and in my garage. It’s seen one rain shower in three years, unfortunately the other day when it was parked outside while I was using the ramp in the garage. Whether this is a coincidence or not, I don’t know.

I’ve noticed the following have ceased to function;
N/S & O/S brake lights
N/S/R and O/S/F indicators (the remaining ones don’t flash fast, using the hazard warning lights don’t make a difference to what functions)
N/S dip beam

After an initial bit of research and look at wiring diagrams it looks as though the lighting control module behind the headlamp switch might be suspect-could anyone shed any more ahem, light on the matter? Is there any testing I can do to confirm?

I have a multimeter and PScan.

Thanks!

[Yorkshire GOC]

It is known for water to effect the Light Switch Module - worth having a look for any water in the LSM - easy to take the facia off and the 2 retaining self tappers - you can then see if any water/damp on the circuit board and dry accordingly.

saying that very unlucky if one shower in 3 years.

[itcaptainslow]

Originally Posted by Yorkshire GOC

It is known for water to effect the Light Switch Module - worth having a look for any water in the LSM - easy to take the facia off and the 2 retaining self tappers - you can then see if any water/damp on the circuit board and dry accordingly.

saying that very unlucky if one shower in 3 years.

Didn’t realise water could make it that far! I’ll remove the fascia and have a look, thanks.

[raykay]

Check fuse 9 in the engine compartment fuse panel, that feeds those lights (and the o/s main beam) via a Brown/Orange cable to the LSM.

[clf]

Originally Posted by itcaptainslow

My 75 has decided it’s going to full on strop since having a daft amount of money spent respraying & rechroming it...

A bit of background-it’s a dry use only car, currently SORN and in my garage. It’s seen one rain shower in three years, unfortunately the other day when it was parked outside while I was using the ramp in the garage. Whether this is a coincidence or not, I don’t know.

I’ve noticed the following have ceased to function;
N/S & O/S brake lights
N/S/R and O/S/F indicators (the remaining ones don’t flash fast, using the hazard warning lights don’t make a difference to what functions)
N/S dip beam

After an initial bit of research and look at wiring diagrams it looks as though the lighting control module behind the headlamp switch might be suspect-could anyone shed any more ahem, light on the matter? Is there any testing I can do to confirm?

I have a multimeter and PScan.

Thanks!

Bit of a long shot, but has worked for me in the past after buying a car that had been stood for a while. Unplug the multi plug, as well as removing the bulbs. The contacts were not corroded, and but I could only assume it to be a dry joint. But after doing this, it worked fine, and never gave an issue, not even a blown bulb if I recall (wasnt a 75). But it is a free and easy check.

[COLVERT]

The LSM on my car caused problems. I took the plug off two or three times then sprayed the contacts with WD 40. No problems since for several years now.

[itcaptainslow]

So...no fault codes. FL9 intact (checked for continuity). Removed, unplugged and replugged the light control unit whilst checking the pins for contact/corrosion (all OK).

Cured by disconnecting the battery overnight and reconnecting. Weird but simple!

[itcaptainslow]

Thought I’d update this. The fault returned.

After a bit of investigation and a hefty clue being the headlamps flickering when I closed the bonnet, I found a multi plug that had backed out of its housing on the bottom of the engine bay fusebox.

Touch wood it’s been good since!