Jump to content

GT6 Mk3 Main & Dip Beam


Alan C
 Share

Recommended Posts

Hi Everyone

 

I'm just finishing off a fuse box upgrade which will increase the number of fuses from 3 to 16. I've come across a slight snag with the headlights. I've wired the dip beam through a relay controlled by a 20A fuse.

I ran a separate circuit for the main beam but it looks like the main and dip beam have one and the same supply, at least on my car. Both the workshop and Haynes Manuals seem to show a separate supply.

Has anyone come across this before?

I'm going to dismantle the column switch and see if it's possible to separate the two.

 

Cheers

Alan

Link to comment
Share on other sites

The main dashboard lighting switch has an unswitched Brown feed. On the second terminal is a Red/Green which is the feed for the side and tail lights. The third terminal has a Blue cable which goes to the dip switch and is a single feed for the headlights. Consider the dip switch as a splitter that directs volts to either main beam, Blue.White cable or dipped beam, Blue/Red cable.

 

An improvement in headlamp brightness can be obtained by fitting relays to both dip and main beams.The relays take the load and the losses from the lighting and dip switches and should result in less losses and brighter headlights.

There are no changes to the main lighting switch needed. Disconnect the blue and red and blue and white wires that come from the dip switch and (using two relays) connect them to pin 85 on a standard four pin relay. Connect 86 to earth. This will operate the coil and switch the contacts when the lighting switch is on in the headlamp position and depending on its position either the main beam or dip beam relay will operate. Connect the mating blue and white and blue and red cables which go to the headlights to contact 30. You will need to bring a fused supply and connect it to pin 87.

 

I hope this helps but feel free to drop me a PM if anything needs clarification.

 

John

Link to comment
Share on other sites

John

 

Thanks for the info.

What you've described is actually what I've already done. I used a period Lucas relay situated on the RHS of the battery box. Handily there are two holes drilled in the side of the box which match the relay mounting bracket. It seems Triumph we're expecting to have to mount at least one extra relay at some point. Or it could be to accomodate the horn relay on LHD cars.

The master light switch now only acts as the relay control and direct feed for the sidelights. Strangely both wiring diagrams I have show a purple lead going to the dip switch from the middle fuse. This looks to all intents and purposes like a separate supply for the main beam. There definitely isn't one there in reality. Doubly confusing is the fact that there is a purple wire with a connector under the steering column. After much head scratching I discovered it's for the ignition courtesy light This is where the wiring diagrams show a double connector and a supply to the main beam. It's the right wire gauge for the it but perhaps Triumph decided it was cheaper to omit it and hopefully no one would notice.

It just means that I now have a spare fuse which can be used to sub divide another circuit. The top candidate for this is the radiator fan and water pump manual override plus the anti run on valve. They're piggied onto the heated rear screen at the moment. The logic behind this was if it's hot then you need the cooling system at maximum and obviously no requirement for the heated screen. Not sure how sound that logic is but now we'll never know.

I've also successfully fitted the windscreen recess drain pipes-photos to follow eventually!

 

Cheers

 

Alan

Link to comment
Share on other sites

John

 

Thanks for the info.

What you've described is actually what I've already done. I used a period Lucas relay situated on the RHS of the battery box. Handily there are two holes drilled in the side of the box which match the relay mounting bracket. It seems Triumph we're expecting to have to mount at least one extra relay at some point. Or it could be to accomodate the horn relay on LHD cars.

The master light switch now only acts as the relay control and direct feed for the sidelights. Strangely both wiring diagrams I have show a purple lead going to the dip switch from the middle fuse. This looks to all intents and purposes like a separate supply for the main beam. There definitely isn't one there in reality. Doubly confusing is the fact that there is a purple wire with a connector under the steering column. After much head scratching I discovered it's for the ignition courtesy light This is where the wiring diagrams show a double connector and a supply to the main beam. It's the right wire gauge for the it but perhaps Triumph decided it was cheaper to omit it and hopefully no one would notice.

It just means that I now have a spare fuse which can be used to sub divide another circuit. The top candidate for this is the radiator fan and water pump manual override plus the anti run on valve. They're piggied onto the heated rear screen at the moment. The logic behind this was if it's hot then you need the cooling system at maximum and obviously no requirement for the heated screen. Not sure how sound that logic is but now we'll never know.

I've also successfully fitted the windscreen recess drain pipes-photos to follow eventually!

 

Cheers

 

Alan

 

 

Great minds again Alan!

 

The purple wire going to the dip switch may well be for the headlamp flash which has a separate feed and this has a connector for the interior light which like the headlight flasher needs a constant live.

 

Well done for putting the drains in. Please do post a picture or two when you can.

 

John

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...