Its all gone dim (headlights on Metro)

[boilerbeasty]

My wife's metro (1993) - generally OK, but the headlights have gone quite dim.
Full beam seems quite bright, and the indicators seem ok, so I don't think it is the battery for example.

 

[keyplayer]

If you're sure the batt. is ok check the lenses for chips/ leaks which will dull the mirrored surfaces, if they're ok clean your headlight earths. only a starting point.

 

[bobsp]

Or alternator, do the lights get brighter when the car is revved?

 

[boilerbeasty]

I had another look with the car stationary and me pressing the switches rather than asking my wife why she didn't have the lights on !!!

The 'sidelights' come on, but not the main beam ones. Also, I can't switch on the full beam lights (i.e. blue light on the dash board) , but I can 'flash them'. Does this sound like some kind of wiring problem ? Or has a fuse gone ?

I'm glad its getting lighter and she doesn't need to drive in the dark at the moment...

 

[MANDATE]

Hi boilerbeasty,
As far as I'm aware your headlight circuit is switched on by a relay and the relay is switched on with your dashboard switch.
The problem could be a fuse or the wiring, but I would suspect the relay.

If you remove the relay you can test it by energizing it (12 volts) across the solinoid while you have a continuity test meter across the headlight circuit terminals.
I did this on a escort and found the relay worked fine.
I next bridged the headlight circuit terminals in the fuse box using 6 in of insulated wire, headlights came on so no problem there.
I then bridged the primary circuit with a 12 volt tester and switched on and no problem there either.
I did however note one of the terminal sockets looked dodgey and thought it might not be making contact with the spade on the relay and this did turn out to be the cause.