Actually your first statement is not entirely true. Early cars that used the on dash rotary headlight switch do not use a "module" that are used on the later cars. The early cars for which we were troubleshooting used a rotary headlight switch where it would pass the 12 V power through it to the lamps rather than control a heavier relay to to do the work. The wire diagram shows this by path described where 12volts works it way through the ON switch to the normally relaxed Hi beam/Low beam relay. This is the same metal relay shown in the red car photo. The only way this relay is energized is with HI beam stalk movement, either momentary towards you or detent away from you. So the job of the early stalks was for HI beam action by energizing the relay for hi beams and low beams when relay is relaxed.
Newer cars (92 -96)use a module with a "flip/Flop circuitry where a momentary pull is high, another pull is back to low. This happens in a rectangular black box mounted on the left side inner wheel arch. The headlight main switch is on a small three position switch on the stalk itself. The module type wiring is on the first wire diagram in this post.

 

Thanks for the clarification. It looks like the circuit i have showing the module, dated '91, is actually for the 92MY.

 

Ok, so in the case where you have the black larger module, the the momentary stalk pull even with main headlight switch off, happens in the module by applying that momentary ground through the stalk to the module and completing the ground for the high beam only coil to pull. You can see that boxed "4" supplies the power to the high beam lights as well as one side of the coil where it waits for the stalk ground to complete it thus giving you Hi beams during the day with main switch off.
With Main switch ON, 12V power now comes from the switched on "headlight relay" and enters the module and allows the transistor logic flip/flop action of the stalk to control hi beam /low beams that way.

 

 

I'd agree with that as my own headlight module in my '95, can be intermittent. It will be on normal beams and if I toggle to Hi beams and back to Low, I lose the lights completely on Low. HI works, but I have to work at it to bring the Low or normal, back on. Somebody on this forum has taken the black module box apart and either cleaned up the contacts or re- flowed the solder joints with good results, which I will also do.

 

It's easy to take apart and resolder. I actually had to change the transistors in mine, as one of them had failed with a short circuit that left the headlights on permanently.

 

Which relay type did you have that you repaired, the older metal relay shown in the red car or the later Lo/Hi toggle type black plastic module.

 

The later, black one.

 

Alright, thanks. It's now on my to-do list.

 

Cool. They do seem to be a little troublesome and are about £80 to replace. However, the only things that can really go wrong are the capacitor and the transistors, so I replaced all three for a total cost of about £4. Seemed a worthwhile investment!

 

 

First of all apologies for taking an age to do this. I took off the metal relay, and accidentally dropped it. I took it apart and the top bit that covers the coil has broken off so I've bought a new black plastic one which was quite awkward to fit - there is not much room to squeeze those five contacts in and hey presto the daylight flash now works! Only trouble is the offside outer headlight now does not work on main beam - maybe that's another thread for another day. Cheers all.

 

Check fuses as the output of each beam is after the relay.

 

Will do but wouldn't both the inner and outer headlight fail main beam if it were the 10amp #3 fuse in the black box? It's only the outer right headlight that is not working for main (high) beam. Could it be the bulb?

 

By "offside" I assume you mean the left side or non-driver's side of the car for UK if you are right hand drive.. If so, the left LOW beam or Main beam bulb is served by fuse #4 for left. It goes to one element (LOW)of the outside bulb.(outside bulbs have two internal elements, H, L, where the inside "high beam" lamps have only one). In low beam or Main beam as you call it, just the "L" Low elements of the outside lamps are served by fuses #4 and #2. When High beams are selected with all lights on, #5 and #3 serve the inner high beam lamps and each H element of the outer lamps. So all elements of all lamps are powered.
So, your "offside outer headlight now does not work on main beam"...could still be fuse #4 or yes, low element of the outer lamp, which means the whole lamp. Check the plug/connector to the lamp first after confirming the fuse is good.

If my offside/onside is all off, then just reverse my description.

 

Offside ( driver side) outer headlamp is now working on main beam - it was a connecting issue where the wire joins into the plastic connector which itself connects to the bulb. When i moved the connector, the light came on. I think the loose connection is where the light bulb connects to the connector rather than the wire as the voltmeter always had a reading when applied to the connector.
Carsnplanes you are a star.

The car has passed it's MOT - it's been quite a journey. It looks like a flying saucer from the rear because the springs I bought were too long but that is another story for another thread.

 

Hey glad it worked out! I guess you'll be a flasher!