Looking for info on wiring/electrics. For a HJ tonner.

HEATER
What current does the heater fan draw?
I'm not sure what size wire to use without knowing how much power is required.
Yes, one of these days I'll get a current draw measuring ammeter gauge thingy, but until then...

WIPERS
And what do the wipers draw? Again for wire sizing.
Also is it worthwhile running power through a relay to the wipers to power them. Mine are a bit sluggish but it could also be that I've got the wiring wrong. From a quick look it seems that the wipers are powered by earthing the relevant terminal through the switch? Is this right? None of the switch terminals seem to have any connectivity.
The inbuilt washer pump has long perished so an accesory pump is used to pump the water instead.

LIGHTING SWITCH
Secondly can anyone explain the lighting switch?
There are 6 slots being used on mine.
Red from the fuse panel. I assume this always provides power so the relevant lights can be turned on without the ignition being on.
A doubled up terminal with a Purple and Dark Brown wire both in the same slot. These run the park/tail lights when the switch is pulled out for one click.
A Dark Green wire running to the dash illumination lights. This is a variable feed which allows the dash lights to be dimmed as the knob is rotated.
A Dark Blue wire, changed because I didn't have any Light Blue as would originally be in there. This runs to the dip switch to power the headlights when the switch is pulled out fully.
All good so far, I hope.

But the Orange and White wires confuse me. They are both connected to the interior light but I can't work out what it is happening. There aren't any door switches or footwell lights.
The Orange is a doubled up terminal with two Orange wires. One runs to the fuse panel, the other to the interior light. And the White wire runs to the interior light as well. This seems a bit complex so I think I'm missing something here. Somehow related to turning the interior light on by fully rotating the knob and/or using a door switch? Any clues?

There is also another unused terminal on the switch. It is the upper left one as you look at the mounted switch which AFAIK has never been used. Any idea what that does?

Thanks.

I've rebuilt quite a few of the wiper motors, and measure the current on all of them as part of testing.
They draw anywhere between 2 and 4 amps on high speed at 13.5V.
The standard wire size, connectors and switch should easily handle that current.
The heater fan motors draw a little more, but not much.

The "little rubber block" is the junction between the short piece of 'fusible' wire & the copper main 12V feed.



Remember that the alternator on these old girls is only 35-40A output (55A with a/cond) so if you had too many appliances switched ON, the battery would go flat pretty quick. As a matter of fact if you headlights on hi-beam, wipers on fast speed, heater on fast fan, by the time you add in the current draw of the ignition system, things are a bit marginal even then.

Dr Terry

Great thread, and great information from all involved.

I've run into my first issue with my new car, some genius when they rewired the front end wired the headlights through the stop tail fuse, and the extra load blew 2 15A fuses last night, so I had to get it towed the last part home in the dark.

I'm hoping the fix will be as easy as finding the supply wire from the fuse box and replacing it with a wire from the battery.

Can you buy cables with fusible link in them from Repco etc.?

What I used to do when I fitted 130W or 100W lamps was to mount a New Era block relay, the modern version in the attached link:

https://www.ebay.com.au/itm/160993200038

You can mount it near to the battery and run a 12V wire straight to it, or mount it over on the driver side where the high beam and low beam wires are easier located. In which case use an inline fuse holder at the battery and run a wire across to it. Use the existing low and high beam wires to trigger the relays and power the low and high beam circuits off the fused outputs. Just replace the 30A fuses with maybe 5-10A for low beam and 10-20A for high beam just depending upon the lamp wattages.

All I used to do was pull the sockets out of the harness plugs at the headlamps, and use a wire with a male spade lug on it to plug into that socket which becomes your relay signal. Then buy the same wire socket that is in the harness plug, solder a bigger wire onto it and push it into the wiring plug - this wire goes to the relay output. The little suckets are held captive in the plug by a little pin which you depress with a little flat screw driver or paper clip and they pull out of the plug. They look like the attached, just buy the ones with the tab on them to be captive. Autobarn etc should have them:

https://www.ebay.com.au/...D%7Ctkp%3ABk9SR7yv5LTDYw

Thanks for the insights. Yes it's a single headlight front, which on first glance has sealed beams.

Part of me wants to leave it original, as I won't be doing a lot of night driving, but the other part of me wants to change it to H4 inserts and put 100/55 globes in with relays.

Edited by user Friday, 8 March 2024 7:22:39 PM(UTC)  | Reason: Not specified

If I put in a relay should I ideally run a wire for each side all the way from the relay, or (probably not) run to one side and then branch off to the other side?

Also with the earth wire from the headlight plug do I run it to earth near the light each side or run an earth wire back to a good earth somewhere?

I found this to help me if I go down the relay road:

I'm not putting driving lights on this 😁.

I wouldn’t either but I wouldn’t be modifying the wiring if it’s original.

Which is why I put a monster light bar on my Ram. Standard lights were junk.