Headlight woes

Discuss Electrical problems here.
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
Post Reply
harveyzone
Newbie
Posts: 6
Joined: Tue Nov 20, 2018 9:31 am
MMOC Member: No

Headlight woes

Post by harveyzone »

Hi there,

Any thoughts on this...

One headlight (nearside) works fine.
One headlight (offside) dipped beam lights very dimly, and full beam doesn't work at all.
Side lights/indicators all work fine.

I first thought it was a dead/dying light unit, so I popped it out to swap for a spare that I have lying around, only to find that a previous owner had swapped sealed beams for halogen units. Anyway, I put my spare in to test it with the same results - dim dipped beam and no full beam.

As I understand both headlights come off the same cable run, with the offside light being the first in the series, so this suggests that the fault is in the short bit of cable from the join to the light, but these all seem good.

Any ideas?

Cheers,
Tom.
Tom Harvey

Image
1978 Triumph Spitfire 1500
1970 Morris Minor 1000, 2 door saloon
ManyMinors
Minor Legend
Posts: 2753
Joined: Tue Nov 11, 2014 9:41 am
MMOC Member: No

Re: Headlight woes

Post by ManyMinors »

It is almost bound to be a poor connection or two - and probably a poor earth causing the "dim" lamp. Take the connectors apart and clean everything - ideally replacing the connectors.
harveyzone
Newbie
Posts: 6
Joined: Tue Nov 20, 2018 9:31 am
MMOC Member: No

Re: Headlight woes

Post by harveyzone »

Earth sounds like a good call. I assume both full and dipped would share an earth. Not sure why I didn't think of that.
Do you know where the head lamp earth to? Is it in the engine bay or in the wing/light assembly?
Tom Harvey

Image
1978 Triumph Spitfire 1500
1970 Morris Minor 1000, 2 door saloon
oliver90owner
Minor Legend
Posts: 1655
Joined: Thu May 12, 2016 6:33 am
MMOC Member: No

Re: Headlight woes

Post by oliver90owner »

Btw, lights are wired in parallel circuit, not series. Each is fed with 12 volts. You have a voltage drop somewhere - either the feed or the earth. Lamps have three connections - two lives and one earth. If one filament lights satisfactorily, it is less likely to be that earth connection?
harveyzone
Newbie
Posts: 6
Joined: Tue Nov 20, 2018 9:31 am
MMOC Member: No

Re: Headlight woes

Post by harveyzone »

Bingo - found it. The earth is a bullet connector into a little clip on the inner wing. It had pulled out. Pushed it back in and they all work fine now. I think I was thrown because dipped beam worked albeit dimly, but I should have checked earths as my rear lights on the Spitfire have been plagued by weird earthing problems! Sometimes all you need is a sounding board to point you in the right direction!

Thanks all... Now on to the windscreen wiper problems, but that is another story, and maybe another thread if I get nowhere! :lol:
Tom Harvey

Image
1978 Triumph Spitfire 1500
1970 Morris Minor 1000, 2 door saloon
Post Reply