superglow wiring questions for 24v bj42

[jim land]

Hello , im trying to understand the stock wiring for the relays on my 42 , a Wilson switch is planed and i want to use the stock round relay and b+ wire that is already connected to it

1- im not sure if i can use the blue wire from the relay to feed the glow plug , in stock form it is connected to the starter and i dont see this on stock wiring diagram i found with search
maybe a PO mistake when he put it back together after the frame off

you can see how it is now on the high tech wiring schematic i make
and some pics to help you to help me.

 

[jim land]

pics

 

[jim land]

more

 

[jim land]

the relay next to the timer box look like the starter relay , why the other relay connected to starter too

 

[lostmarbles]

Hi Jim.


Yes. I too think the relay beside your preheat timer is your Starter Relay (that simply uses the feed from the "start pin" on your ignition switch to send juice to the solenoid on your starter motor whenever your key is turned to the "start/crank" position). But it looks to be aftermarket with new wires spliced into the old loom. (The colour-codes of the old loom wires match what my wiring diagram says they should too for the Starter Relay as you can see below)

This should be your preheat wiring ... based on what the 1983 wiring FSM says for a BJ 40-series:

And here's another image that gives the terminal IDs on the timer:

Does this help Jim?

(I don't know why any of the preheat wiring should be going to your starter motor.)

 

[jim land]

i followed the blue wire that exit the round relay (on the rad support) and it is connected to the starter , and i was stumped , i bet it is a mistake at the reasembly in the past

 

[jim land]

so i can remove the blue wire on the starter with no problem ? and use it to feed the busbar on my Wilson set-up.

now i know why the glow system never worked right , the previous owner is and old friend ,he bought it new in 84 ,frame off and gozzard in early 2000 , it was his summer car only , he sold it to me last summer .

thanks you Tom

 

[lostmarbles]

i followed the blue wire that exit the round relay (on the rad support) and it is connected to the starter , and i was stumped , i bet it is a mistake at the reasembly in the past

so i can remove the blue wire on the starter with no problem ? and use it to feed the busbar on my Wilson set-up..........

I'm puzzled about some things here Jim.

My starter motor on my 12V BJ40 has only two factory-installed external wires coming to it and the first diagram in post #5 suggests your 1983 24V BJ42 should be the same.

The first wire is really "a big thick cable" and it comes direct from my battery. Here I assume is your equivalent wire that I've arrowed in red (carrying 24V direct from your batteries):

Can you confirm that this "wire" is big and thick and comes direct from the 24V terminal of your batteries?

And I believe the second factory-correct wire I'm seeing is the one I've arrowed in blue. If I'm right, it should be coming from your starter relay and going to a terminal under that second rubber boot. Is that correct?

So in addition to these factory-correct wires, it looks like your PO has added a "Blue Wire" and a "Black-With-Orange-Stripe Wire"..

Where do they connect to your starter motor? Do they connect under either of those two rubber boots?

Sorry - But your wiring sketch doesn't even show any wire at all connecting your starter motor directly to your batteries... Was this a mistake on your part?

Unfortunately I'm reluctant to give a straight answer to your question right now because there's too much I don't understand. (And I don't like the idea of leaving any wiring there that isn't fully understood and that may not serve any useful purpose.)





PS. The starter motor you have there is 24V is it not? One idea I had is that maybe your PO experienced a starter motor failure at some point and perhaps due to supply problems - shagged around with relays and whatnot to get a 12V starter to work perhaps using some of the old preheat wiring that was judged to be no longer wanted? But then again those Blue and Black-Orange wires look far too thin to be carrying starter-motor current so probably best to dismiss this idea. (And neither are any of the preheat relays big enough to carry starter-motor current.)

 

[jim land]

yes , the red arrow is a fat wire from bat and blue arrow is from starter relay , im sure the blue and the black-orange wire have been installed on starter by mistake when the wiring harness was reinstalled on the new tub , the glow plugs connection is just a feet higher .

today i will try to start after removing the glowplugs wire from the starter.


ps: the big starter wire was not on my sketch because i was focus on the relays wiring only.

 

[jim land]

i found this pic from an old thread , it confirm the correct location of those wire

things are more clear now

 

[lostmarbles]

OK. That clarifies things with me too Jim and I'm now more relaxed about this.

So definitely remove BOTH those extra wires from your starter motor so that it is left with only the big thick 24V cable (I arrowed in RED) and the wire that operates the starter solenoid (that I arrowed in BLUE).

I assume you are now planning on seeing if the factory "superheat preheat" will work rather than immediately going to a "Wilson Switch" manual preheat?

If so..

Check that you have the correct 14V glow plugs in place for "superheat".... especially because of this cruiser's history. (Owners commonly replace plugs and commonly get incorrect advice on which ones to buy.)

And this "bent short section of busbar" is your "current sensor" (that I've arrowed in thick red):

The wire connected to it near the start (arrowed in thinner green) is the B-wire connected to terminal 3 of your timer and the other one (arrowed in yellow) is your BR wire connecting to terminal 9. Together they give your timer a different voltage reading (feedback) depending on how much current your glow plugs are drawing.

So the other ends of those two wires must have a connector that connects them to those terminals on your timer.

I'll stop here ... because maybe I'm wasting my time saying all this Jim..... I'm thinking ....Was this all taken apart on your BJ42? Or does what you have there visually match this photo you've found? (Also I don't really know whether you want to try and get your superheat preheat working at all of course.)

If it's been messed with and you've got to reassemble the superheat engine stuff yourself, I imagine it may be tricky getting the insulators in the right place so the current goes where you want it to (rather than short-circuiting). (I can probably help you through it though..)

Anyway.... going from your photo I'm assuming this is what we've got:

So it looks like the diagram from post#5 has one wire correctly colour-coded and the other listed as "Black with a blue stripe" (BL) instead of your "solid blue" (L).



PS. That thing on your intake manifold that these BL and L wires attach to is not just a "terminal stud". It is your "dropping resistor".
The heat it generates (when the LH relay in the diagram above is energised) is dumped into the manifold.
So the BO wire feeds the current sensor through the dropping resistor whereas the L wire feeds the current sensor directly.

 

[jim land]

yes, the idea of keeping the stock superglow did cross my mind , only if everything is ok, but i need to find the right way to test the systhem , i did remove the L and BO wire from the starter and did some quick testing , the round relay is clicking when i turn the key to on just before start position , but no voltage at the end of the blue wire ( not plug at the engine side ), only on start position (cranking) i got somting like 14v , i also test the round relay with the ( small wires unpluged ) and jumper wire on b+ and ground , it read 24v

it was late and i need to test again tomorrow

thanks for the help

 

[jim land]

Wilson switch win for the simplicity , using all factory parts , round relay with stock connector and wire , B-Y wire now feed the switch , the glow light and go direct to the relay , got my 23v glow plugs from 4wheelauto

 

[RGebbie]

I'm puzzled about some things here Jim.

My starter motor on my 12V BJ40 has only two factory-installed external wires coming to it and the first diagram in post #5 suggests your 1983 24V BJ42 should be the same.

The first wire is really "a big thick cable" and it comes direct from my battery. Here I assume is your equivalent wire that I've arrowed in red (carrying 24V direct from your batteries):
View attachment 1226678
Can you confirm that this "wire" is big and thick and comes direct from the 24V terminal of your batteries?

And I believe the second factory-correct wire I'm seeing is the one I've arrowed in blue. If I'm right, it should be coming from your starter relay and going to a terminal under that second rubber boot. Is that correct?

So in addition to these factory-correct wires, it looks like your PO has added a "Blue Wire" and a "Black-With-Orange-Stripe Wire"..

Where do they connect to your starter motor? Do they connect under either of those two rubber boots?

Sorry - But your wiring sketch doesn't even show any wire at all connecting your starter motor directly to your batteries... Was this a mistake on your part?

Unfortunately I'm reluctant to give a straight answer to your question right now because there's too much I don't understand. (And I don't like the idea of leaving any wiring there that isn't fully understood and that may not serve any useful purpose.)





PS. The starter motor you have there is 24V is it not? One idea I had is that maybe your PO experienced a starter motor failure at some point and perhaps due to supply problems - shagged around with relays and whatnot to get a 12V starter to work perhaps using some of the old preheat wiring that was judged to be no longer wanted? But then again those Blue and Black-Orange wires look far too thin to be carrying starter-motor current so probably best to dismiss this idea. (And neither are any of the preheat relays big enough to carry starter-motor current.)

It depends on the yr of the vehicle. I have 2 1981 bj42. 1 has superglow system wich I think is 12 volt so diff glow plugs. Diff voltage for pre heat to glow plugs. Superglow system does not have wilson switch, It used BO. BW, and BB wires. BO and BB go to the glow plugs via another du dad. It uses a round resistor du dad on the side. It also has a 24volt timer. Im sure Im forgetting something. #2 bj42 has a glow plug relay with 3 wires going to it BY, BR and B . It has via wilson switch and controller/du dad that after holding button gets hot/red. #2 sends 24 volts to glow plugs(i think) There are a couple differences between the glow plug pre heating system. Both my BJ are 1981.