dmaddox's 1981 BJ42 restoration and information thread!

[dmaddox]

Using my new multimeter skills, I traced that thick RB wire.

It is hanging CUT, right next to the 12V dimmer relay. Great. Still, that large connecter doesn't make sense.

Well, I am trying to keep a log of all the wiring issues. THE GOOD NEWS, is that we are getting close. There are only a few issues remaining.

Horns (albeit mounted wrong) are connected:

I decided to shrink tube and wire loom the temp sending wire:

This picture is taken THROUGH the opening of the ash-tray. Some wires are cut here - so I'll have to fix where they cut them:

Dash light appears to be hacked:

No wires going to the "GLOW ON" switch:

There are three-four plugs in the "area" behind the gauge cluster:

One:

Two:

Three and Four:

Getting closer!

 

[DanS HJ-45]

No wires going to the "GLOW ON" switch:

Getting closer indeed! FWIW, not all plugs may be used. Our '79 in stock form had a bunch of plugs that were just left hanging open, although it was a simple US spec FJ-40 may be different.

If you have the "GLOW ON" switch then you may not have the glow position on the ignition switch (and it may be correct that way). I haven't seen any stock setups with multiple ways to activate the glow plugs.

Dan

 

[dmaddox]

Good point Dan. Some of those plugs were likely not used.

The ignition tumbler however was definitely tampered with. In the plastic "shells" of the steering column, there is a moulded hole were the lock button used to stick up - this ignition tumbler does not have a lock button. From what I know - ALL diesels had the reverse key turn to glow the system before starting (this would explain why i can stick a flat screwdriver into the ignition switch while it is removed, and twist it backward into a "glow" position). It was only on the NON-Superglow systems that a "GLOW/ON" switch was outfitted to smooth out a rough idle during the cold seasons.

I need to clean my fingernails....those pictures make me look like a hillbilly. Ha ha ha...

 

[fjbj40]

The big RB wire goes into a fusible link which is then connected to your l/h battery. This known as the evil tap for the 12 volt headlight. It sends power to the dimmer relay which closes and then sends 12 volts to the other headlight.

Daryl

 

[dmaddox]

Brilliant! Thanks Daryl. Makes absolute sense. However - I wonder why it's not on the wiring diagram. . .

 

[fjbj40]

I think those other plugs behind instrument may be for the turn signal and high low beam on your steering colum.

My BJ40 had the turn backwards glow and the switch also. pre-heat by turning key backwards and then keep her smooth untill she warms up by momentarily using the rocker switch. I just use the rocker switch for all purposes, pre-heat and warming up.

One of those plugs may actually be for the glow rocker switch....

Daryl

 

[fjbj40]

Look harder cause it is on my diagram.....are you using the Canadian BJ42 diagram? There is a differance in non Canadian BJ42's

Daryl

Brilliant! Thanks Daryl. Makes absolute sense. However - I wonder why it's not on the wiring diagram. . .

 

[dmaddox]

Daryl - thanks bud. It looks like I am just using a generic 1981 BJ40/BJ43/HJ47 Wiring diagram. Any chance your 1981 BJ42 diagram is in a .pdf or jpg?

thanks again,

 

[bj40green]

The big RB wire goes into a fusible link which is then connected to your l/h battery. This known as the evil tap for the 12 volt headlight. It sends power to the dimmer relay which closes and then sends 12 volts to the other headlight.

Daryl

Thanks for letting us know. It's the famous "Evil Tap".
Now I know why it's not in my wiring diagram.

Rudi

 

[fjbj40]

I am old school, it is on paper

That being said, alot of the colors and the way the harness is set-up is alot like the 1980 BJ40, that which I am familiar.

Daryl

Daryl - thanks bud. It looks like I am just using a generic 1981 BJ40/BJ43/HJ47 Wiring diagram. Any chance your 1981 BJ42 diagram is in a .pdf or jpg?

thanks again,

 

[seapotato]

One of those plugs may actually be for the glow rocker switch....

Daryl

I think you're right...

I'll check the colours on mine when I get home, (unless someone beats me to it) our trucks are close to the same vintage.

cheers,
ryan

 

[Greg_B]

This tread might help. https://forum.ih8mud.com/diesel-tech-24-volts-systems/68379-78-bj-40-headlight-diagram.html IIRC even that sub drawing is a little wrong, but hope it helps some.

gb

 

[45Kevin]

From memory that un-identified plug by the horn could be for the DS turn signal on the fender.

Just had mine apart on the FJ45, but if I recall it was 2 wires like yours. I thought that the newer models went with a wired ground though, making it a three wire bundle.

 

[profff]

Dallas-

Still following this. Glad you didn't sell it. Can't wait to see the video where that 3B is spinning again.

 

[fjbj40]

plug 3, WG/BY is for the glow rocker switch, just checked t on my rig...

Daryl

I think you're right...

I'll check the colours on mine when I get home, (unless someone beats me to it) our trucks are close to the same vintage.

cheers,
ryan

 

[fjbj40]

yes a good read for the evil center tap,

Dallas, as you can see from Greg_B's
post you will see the RB gets its power from the l/h battery and goes through a .5mm(i think) fusible link, at least thats what it looks like in the drawing from that link.


Daryl

This tread might help. https://forum.ih8mud.com/diesel-tech-24-volts-systems/68379-78-bj-40-headlight-diagram.html IIRC even that sub drawing is a little wrong, but hope it helps some.

gb

 

[dmaddox]

plug 3, WG/BY is for the glow rocker switch, just checked t on my rig...

Daryl

AWESOME!!! Thanks man. It's connected and we have one more plug solved!

-dallas

 

[subzali]

That R-B wire/plug doesn't ring a bell for me......

Glad to see you're learning a bit with the multimeter. The things you need to know for automotive use are really how to check continuity, voltage, and perhaps resistance (not that very low resistance is continuity).

Once you know that stuff, you'll want to keep one in your glovebox all the time, because it's amazing how useful they can be on the side of the road.

Dan

And current. Had to relearn that one while trying to find a current drain in my electrical system recently

 

[dmaddox]

Which air cleaner system is correct for my rig:

1:

or

2:

 

[fjbj40]

#2 is the type which is in my BJ40, well it really is not a 1980 BJ40....it is a 74 FJ40 converted to a BJ40.
But the air filter housing is a BJ factory unit. I think pic #1 is a later style BJ42.

Daryl