Headlights not work!! And now after fixing, head, tail and side lights don’t work !!!!

[cmcmill01]

In the continuing saga of getting my very nice-looking 1978 FJ40, but don’t judge a book by its cover! I decided to give the headlights a go!

The headlights had worked, and then stopped a bit intermittently.
I was investigating the wiring to find out why the headlight switch also closed the AC motor, which I think is the large blue and black cable on the wrong side of the fuses.
Checked both sides of the fuses and see 12v, so they are good.

When I started this investigation, the tail and side lights worked, now after poking about, they don’t work along with the headlights.

The indicators and the horn work; the horn is one of the 3 circuits that should always be live.

Also, I don’t understand 3 wires on the switch and four wires on the plug!!

Tested the switch, and everything seems to go to zero resistance as expected.

Have downloaded the wiring diagrams from Coolerman and Cruisercult, but still at a complete loss about what’s going on! Any advice greatly appreciated!

 

[nabbasi]

Just to start, is this a US spec 40?

I only see 3 wires that are the correct color or gauge going into your fuse panel. That’s going to make troubleshooting this very difficult, unfortunately.

On an original 1978 harness, power comes in from the battery+ (ammeter wire), which provides headlight wire (Large Red wire) power. This goes into the headlight switch. When the switch is pulled, it sends power out the Red/ White to the dimmer, and dimmer sends Red w/ a green for low beam, Red w/ yellow for high beam.

 

[cmcmill01]

Just to start, is this a US spec 40?

I only see 3 wires that are the correct color or gauge going into your fuse panel. That’s going to make troubleshooting this very difficult, unfortunately.

On an original 1978 harness, power comes in from the battery+ (ammeter wire), which provides headlight wire (Large Red wire) power. This goes into the headlight switch. When the switch is pulled, it sends power out the Red/ White to the dimmer, and dimmer sends Red w/ a green for low beam, Red w/ yellow for high beam.

Nope Asian import to UK, and I know the PO looks to have hacked together the wiring. Not sure on the switch having 3 wires only

 

[charliemeyer007]

In pic 2 there are two blue wires with silver dots on the same side of the fuse box but on e different fuses - seems odd to me.

Go to the head lights and trace the wires back to the switches then to the fuse box while drawing a diagram of what is there then compare to factory/book WD. The book is generally correct, PO's work - not so much.

Back in my Signal Corps days we would call that a many aspirin sandwich job - PIA. Light bulb test light very handy, or a multimeter with audible.

 

[pbgbottle]

the Toyota harness does not have single wire connections on the fuse box. Well it might have one or two extra ones. But it usually has a 2 or 3 large plastic plugs that push on and contain all the wires in the correct locations. Hmmm. In 1978 anyways.

 

[procomsignathid]

In your rig, do you have separate fuses for parking lights/tail lights and the headlights?

I ran into issues on my 1978 that was also poorly bodged together, because the headlight switch was from the wrong year (where there was a single fuse for all lights on the truck). My issue was that I kept burning fuses with the headlights on, which it was a bit different from what you’re describing.

Your headlight switch definitely looks to be of a older generation than 1978, but I could be wrong.

Given the state of the electrical situation you have going on there, you might have to spend some time determining how it should be wired before you can fix the issue.

 

[procomsignathid]

I’m not sure if it’s different for a Japanese spec truck, but that headlight switch connector should have five wires for a 1978 US spec:

1. One power wire from the “headlight” fuse
2. One power wire from the “tail” fuse
3. One switched wire that goes to the headlights when the switch is pulled into the second position
4. One switched wire that goes to the instrument cluster lights (and heater/dashboard lights) when the switch is pulled into the first position. This is a separate wire because some trucks of this generation had a rheostat on the headlight switch that allow dimming for these lights.
5. One switched wire that goes to parking/corner lights when the switch is pulled into the first position

 

[cmcmill01]

In pic 2 there are two blue wires with silver dots on the same side of the fuse box but on e different fuses - seems odd to me.

Go to the head lights and trace the wires back to the switches then to the fuse box while drawing a diagram of what is there then compare to factory/book WD. The book is generally correct, PO's work - not so much.

Back in my Signal Corps days we would call that a many aspirin sandwich job - PIA. Light bulb test light very handy, or a multimeter with audible.

The 2 wires that have different covers, blue and black I think provide the aftermarket AC with power, they have their own inline fuses

 

[cmcmill01]

So this is the way to find for the side lights that the fuse wasn't seated correctly!! Absolutely mental when you think you have checked everything!!

Think light blue is the cable from the ammeter, and the large pink on other side is the single power to the lights.

So got the sides lights and tail lights working, now to figure the headlights

 

[charliemeyer007]

There you go. Slow and steady wins the race. People often don't do a job thoroughly inspecting stuff, because it hard to see in tiny poorly lit spaces and then there the I already looked at that 3 times or its a new part syndrome.

That's why they write down all the checklists for stuff like rockets, submarines, airplanes is to help people not forget things when the chips are down.

 

[cmcmill01]

So still working through this, the headlights are actually powered by a aftermarket harness!! So after chase loads of spare wiring and tested a few things, it looks like the 12v is coming on at the connector and switches between high and low but no lights!!
I have put in the bulb and tested the voltage and it looks like 12v at the earth, I think this means bad earth so need to figure that out!!!

 

[cmcmill01]

Seems, an H4 after marker kit had been installed, think I need the bracket kit maybe as it's very untidy with all the spare wiring, tie wrapped as much as possible!!

And the Issue of why the headlights were not working was that the battery connection for this kit was not connected correctly!!