Headlights issue

[nfs56]

Hey guys

Recently bough my first Lancruiser, I have an 84bj42 and currently the headlights are not working
and I am having trouble figuring it out if anybody could help. I tested all the red/yellow wires from the dimmer relay to headlights and continuity is good, as well as the red/green. I have the 24v live feed coming into the dimmer relay as well, I am suspecting the dimmer relay but was wondering if there is a test i can perform. possibly feeding 12v to pin 4 and listen for the click? All my other lights work perfect, just the headlights are my issue. if i supply 12v to the bulb they work no problem.

thanks,

 

[bj40green]

You have a tricky one. The relay is 12V (pin 8) but it has 2 x 12V sections.
One section switches between 24V and 12V and the other section between 12V and 0V.
Study this diagram very good to understand how it works.

Do you have rear or running lights when you pull the light switch in first and second position?
The relay becomes active when you pull the light switch in the second position.
With the pull switch in the second position there will be 12V on pin 8.
When you flip the High-Low switch the relay should click from high to low (3 or 4 to ground).
You should hear a click in the relay or put your finger on it to feel if it works.

Good luck!

Rudi

 

[Greg_B]

Nice diagram Rudi.

nsf56 - Is your center tap (which gives the 12V to the relay) hooked up and working? It's located on the negative pole of your high side battery. There needs to be a 12V and 24V feed into the relay so it can do it's business as shown in the diagram. Here is an old post that's not near as easy to understand as the diagram above. 78 BJ 40 Headlight Diagram

hth's
gb

 

[nfs56]

Thank you Rudi for that diagram explained, I will admit i could not understand the pins numbers and the location of the them in the connector...

All my other lights work perfect, signals, interior, tail lamps. even the dimmer for the interior lights work.
There is not 12v at pin when i switch into position 2, clearly this is an issue. which means I obviously dont have any clicks coming from the relay.
where does that 12 volt come from? driver side battery fuseable links? if so what wire cause the original owner had a few aftermaket things like additional lights and fuel line heater installed and I had to fix a few wires I could see where broken/corroded. the lights did not work before I fixed these wires and I was hoping they would once I was done. I'll attach pics. I repaired two wires, one that attached to the positive terminal and went into the connection box(you'll see its a brown wire) and the second repair was a red aftermarket wire that had a 20am fuse in line(now a orange wire with a white fuse protector encasing)

gregb, is the center tap wire you speak of the same as the 12v RB wire from pin 8?

 

[bj40green]

RB from pin 8 goes to the center tap with a fusible link.
If you don't have the fusible link (anymore) you can use an in-line fuse.

If you can't read this.... give me your email address and i'll send you the original picture.

Rudi

 

[nfs56]

The fuseabke link at the battery is which one?i assume its driver side battery & the positive terminal? I dont even know which wire to look for, i assume its still RB but if you look at the pictures i uploaded there is nothing of that color

 

[nfs56]

also, what size fuse would I use once if i replaced the fusible link that is there? once I find it that is... lol

 

[bj40green]

Let's start at the beginning.
Take your voltmeter and check for voltage on pin 8 (12V) and pin 7 (24V).
If you don't have voltage...... peel open the wire loom and follow the RB and/or R wire in the direction of the battery.
You have to figure out what the PO did and go from there.

Rudi

 

[nfs56]

24 volt yes, 12 volt no. Thanks ill go from there, was just wondering if i could get a idea of where the stock fuseable link goes... if i should look on the drivers side battery negative or positive pole.

 

[Greg_B]

Stock 12v Center tap is connected to the negative pole of the high side battery: low side being the 1st battery in the 24v series setup. On the Cdn spec BJ42's the right side battery is the low side (1st in series) and the left side battery is the high side (2nd in series) and is the one that has 24v coming off the positive pole. The 12v Center tap is off the negative pole of the high side (left side) battery. It is a single smal wire that comes off of the negative pole.

hth's
gb

 

[nfs56]

And its Red with a black stripe stock, correct?

 

[Splangy]

Check the harness connectors. They're under the passenger side dash on LHD models.

 

[Greg_B]

And its Red with a black stripe stock, correct?

Just had time to look. Yes. It joins up with the wires for the horn, signal and headlight on the left side in the loom that heads underneath the rad, to the main harness on the right side.

 

[Greg_B]

As some one else mention though, you don't know what a PO has done, so the advice to brings the wires out of the loom and see might be wise. I was lucky when I had problems with my 1981 BJ42 years ago as I had a 1984 that I pulled apart, learned...then pulled apart my 1981 and found a PO had cut the 24 wires in the main harness before it headed into the firewall.

hth's
gb

 

[bj40green]

Here is a little advice.... Figure out where that RB wire goes. It should go directly to the battery.
You have to find out what is causing the problem. Maybe the PO was trying to re-route it to an other switch, maybe he was trying to rebuild the headlights to 24V. Maybe the wire was damaged and he replaced it with another color, maybe, maybe, maybe, you simply don't know.

Rudi

 

[nfs56]

Thanks guys, a lot of very helpful tips. Ill get on that tomorrow and take a look for that wire. Its a good thing you guys told me where it should be located cause i was searching on the drivers side and expecting it to be at the positive terminal. This will help alot.

 

[Greg_B]

Thanks guys, a lot of very helpful tips. Ill get on that tomorrow and take a look for that wire. Its a good thing you guys told me where it should be located cause i was searching on the drivers side and expecting it to be at the positive terminal. This will help alot.

The positive terminal would give you 24V. As the diagram shows, there is a 24V and 12V wire that feed into the dimmer relay (24V from the highside battery positive pole and 12V from the highside battery negative pole). The 24V wire goes into the main loom through the left side of the firewall and the 12V wire goes under the radiator to the right side loom, before heading into the firewall to the main loom on the right side. The 24V wire and the 12V wire then meet at the dimmer relay and from there the relay allocates to each headlight pin as needed, so 12V bulbs can be used. Good luck troubleshooting. PO wiring can be a joy.

hth's
gb

 

[nfs56]

problem solved!!! thank you so much guys, i really needed to know where the wiring went and what pole it was on. found it right by the horn and the wire was broken at the connector, the PO had a green wire coming off the battery negative going down to the RB wire, but the green wire was corroded at the connector and just pulled out.

My question now is what amp fuse to put in the inline fuse?

 

[bj40green]

Good job
20 Amp will do the trick.

Rudi

 

[nfs56]

Can't thank you guys enough! This will allow me to drive the cruiser for a couple months before embarking on a body off restoration. At least I can find out what else might be wrong with the truck now.