Headlamp relay loom causing high beam problem

[28hodge 22]

 

 

Ok strange issue, I bought a headlamp relay loom, this one

 

 

https://www.ebay.co.uk/itm/Headlight-Wiring-Harness-Relay-Loom-Upgrade-Headlight-H4-For-VW-Golf-Corrado-Mk2-/254481073999?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=710-127635-2958-0

 

I’ve wired it in and it works fine, until I turn the key to the second position on the ignition, then the high beam bulb on the dash cluster glows very faintly, the lights will turn on no problem on side dipped and then go onto high beam. 

 

This is where the problems begin, switch the stalk to dipped and the headlamps stay on high beam, turn the stalk to side lights and they stay in high beam. On the second position of the ignition once high beam is selected I can’t unselect it. Only way to turn them off is to turn the ignition back to position 1 or off then the lights all work again correctly as they should.

 

With the ignition off the lights work perfectly as they should ignition on in position 2 and they work until high beam is engaged then they won’t turn off. The high beam relay must be seeing current but anyone any idea where from?

 

When I put sidelights on the dipped headlamp bulbs do not come on, which I think they should via the resistor? Could this be creating a path to feed the relay or is that just a red herring?

 

Any help as electrics aren’t my strongest subject.

Edited December 8, 2021 by 28hodge

[Anthony 1,003]

Try unplugging the dim-dip relay (on the N/S scuttle panel, along with the horn relay on 1.9 models) and the front driving light relay (far left relay in the fusebox) - do either resolve the issue?

 

I know that the driving lamp relay can behave very strangely and in a similar manner to how you describe without headlights plugged in and won't unlatch once engaged

 

As you describe, the dim-dip system should illuminate the dipped beam lights faintly with the side lights and ignition on by running current via the dim-dip relay and the resistor (located underneath the N/S headlight).  That reduced current would be enough to trigger the relay on that new light loom, and besides, the dim-dip system won't work with that new loom anyway (without re-wiring anyway).

[28hodge 22]

Hmmm, I disconnected and removed the headlamp wiring loom last night to make sure all was still working as it should with that removed, and it does. I'll go back out at lunch and reinstall it and test as you said.

 

However probably worth mentioning that the car has no driving lights in the front spoiler fitted, it'll be used for road rallies and targas and they will just get smashed, and also no relay fitted far left of the fuseboard for them.

 

Am I right thinking the following - 

 

-  The relay in the fuse board far left operates the driving lights in the spoiler, activated when full beam or flash is selected.

 

-  The relay on the scuttle allows for the dipped headlights to operate via the resistor when the ignition is on and only side lights selected on the stalk, routing a reduced voltage through the dipped filament of the bulb.

 

I am thinking that must be allowing enough power to the relay to allow for the relay to stay closed but not enough to initially close it? As my dim/dip system doesn't work anyway unplugging the relay on the scuttle wont make any difference but may allow the relay to close? I am guessing so as the headlight relay loom works perfectly with the ignition in the off position.

Edited December 9, 2021 by 28hodge

[Anthony 1,003]

1 hour ago, 28hodge said:

Am I right thinking the following - 

 

-  The relay in the fuse board far left operates the driving lights in the spoiler, activated when full beam or flash is selected.

 

-  The relay on the scuttle allows for the dipped headlights to operate via the resistor when the ignition is on and only side lights selected on the stalk, routing a reduced voltage through the dipped filament of the bulb.

 

That's correct.  Might be nothing to do with the dim-dip, but removing the relay should rule it out - my thinking was that there's nothing else ignition controlled on the 205 lighting system I can think of other than dim-dip, assuming that your new light loom doesn't have an ignition supply (other similar looms I've seen don't)

 

If you turn the headlights off completely (i.e. no side lights or dipped/full) do the high beams still stay on until the ignition is switched off?

[28hodge 22]

5 minutes ago, Anthony said:

 

That's correct.  Might be nothing to do with the dim-dip, but removing the relay should rule it out - my thinking was that there's nothing else ignition controlled on the 205 lighting system I can think of other than dim-dip, assuming that your new light loom doesn't have an ignition supply (other similar looms I've seen don't)

 

 

No the only feed to the relay loom is from the battery positive pole on the battery.

 

6 minutes ago, Anthony said:

 

If you turn the headlights off completely (i.e. no side lights or dipped/full) do the high beams still stay on until the ignition is switched off?

Yes, once high beam has been selected via either the flash system on the stalk or the switch to high beam from dipped the high beams stay on until the ignition is off when it resets itself. and everything works as it should until the ignition is switched on.

[28hodge 22]

 

heres the loom relay wiring diag

[28hodge 22]

Dim/Dip relay removed and the headlight loom reinstalled and its working as it should. Thanks