Where to splice in relays on a GQ?

[mudnut]

G'day, all. I have been given a set of 100 watt driving lights. As well as the driving light relays I want to add relays to the headlight circuit to cope with the extra current. Can someone please add the splicing points and diagrams to the existing circuit. Thank you in advance

[the evil twin]

Back of the headlamp globes is the easiest and most practical.

Cut the existing loom about 3 inches behind the globes

Use the vehicle side of the drivers globe lo to switch the low beam relay coil and the hi to switch the hi beam relay coil.
Use the same hi beam tap to the coil of the Driving Light relay/s and run one wire from the other side of the coil back to the dash switch then earth the other side of the switch at the dash.

[mudnut]

So does that mean I need two relays for each headlight and one for the driving lights?

[the evil twin]

You will need as a minimum 3 relays... 1 low beam, 1 hi beam and 1 spotties
If you go that way you need the 5 pin relays that have two 87 pins (not a changeover that has 5 pins with an 87 and an 87A)
That way you run the LH beam (lo, hi or driving) off one of the 87 pins and the RH beam off the other pin.

Alternatively you can run a total of 4 which is one 5 pin for low beam, one 5 pin for hi beam and two 4 pin (1 each) for the individual spotties as they pull more current.
or
6 relays, all 4 pin, with one for each beam.

[mudnut]

Since I am letting more current flow through the filaments, do I need to upgrade the negative wire from the the back of the headlights straight to earth?

[mudnut]

I have also noticed that the Haynes diagram shows the negative wire running back through thr dimmer control and the workshop manual just runs thr negatives to earth.

Is that for a different year? Mine is a '94.

[the evil twin]

FWIW, I have only ever seen vehicles wired as per the workshop manual, never like the Haynes.

There is no 'extra' current flowing thru the filaments so the factory earth wire should be adequate... unless you change to high wattage (illegal) globes such as 90/100's or whatever.
I tried hi-wattage in one of my GQ's (a '94 efi) and I got better results with standard wattage "+100" globes.
The other GQ I used those +100 globes and just fitted relays

Just make sure the globe socket is in good condition with no signs of overheating and the body earth is good and the factory wire will be OK

Again, FWIW, I have only seen issues where the socket has melted

[mudnut]

Thanks, ET. I pulled the headlights out to check. They both have black wires and not the black red wire. It will be a lot easier knowing what to do, as I have been putting it off because of the confusion with the diagrams. Now I have to find an auto elec to make me up a new heavier alternator lead.

[mudnut]

This is an expensive project. Here is what I have done so far. I have made loom for the headlights, and one for the driving lights. I have made a clip in stainless steel bracket for the water proof headlight relay box. Also fitted and wired in the relays and retro fitted a Yota relay box to suit the driving lights. I have an auto elec making a heavy gauge alternator cable, which should be ready on Monday.

[mudnut]

This is the circuit of the loom I have made to splice into the headlight. I used the Red wire with the green stripe as the high beam signal to the relay and the Red wire with the blue stripe as the low beam signal.

[Bigcol]

on my GQ I did as ET said - 4 relays
1 x each side for Low/High
1 x each for the spotties

that panel next to the battery - where the factory relays hide, is where I fitted all the relays

unfortunately, I cannot find a photo to show you - sorry

I had a new loom made by a mate and spliced it in behind the Drivers side headlight

[mudnut]

I would have gone down that route, but went with the water proof boxes after my fuel pump control copped a dose of water. It might not look as good but it is easy to get to and there is plenty of space under the bonnet. Also it will be easy to transplant the system into another vehicle if I ever upgrade.

[mudnut]

All wired up and working. The switch doesn't look too out of place either. Just need to align the beams and I'm done.