24v wiring issue - I’m stumped (1 Viewer)

[loftydog]

My starter shorted out melting the post off the battery and a few wires.

I had the starter rebuilt, upgraded and replaced the wiring but running into an issue.

The glow plugs will not heat and the starter will not engage using the ignition. All of the other electrical systems work fine.

I can get the starter to turn over using a screwdriver.

I have 24v coming off the driver side battery. 24 volts at the ignition switch. 24v going into the regulator (on the engine bay firewall by the blower motor) but only 10v at the glow plug relay. If I engage the manual glow plug switch that 10v drops to zero.

I’m not great at testing relays but there has to be something after the ignition that is causing the voltage to drop.

Any ideas???

 

[loftydog]

It’s a 1981 bj42 with a superglow system.

 

[Eurasiaoverland]

Your wiring should be protected by fusible links near the battery, but if you melted the battery post off, it suggests these may have been bypassed. In this case, you need to check everything in the circuit, including earth points. If the fusible links are still present I would start there.

 

[quadrunner91]

Like Eurasiaoverland suggested. Put fuseable links on there prevent this from happening again.
I don’t have any 24v experience, but have you checked the relays and fuses? Relays generally have a signal wire, ground, and two outputs.
If you poke a volt meter on the signal side, you should get voltage with the key on or in start position. If there’s no voltage on the signal wire, and the fuse is good - it may be a melted wire or something else more complicated.

Starter relays are generally on the starter itself, but I bet there’s a relay that controls the starter signal wire.

That’s where I’d start!

 

[loftydog]

Your wiring should be protected by fusible links near the battery, but if you melted the battery post off, it suggests these may have been bypassed. In this case, you need to check everything in the circuit, including earth points. If the fusible links are still present I would start there.

this is what I have

 

[quadrunner91]

I bet your glow plug system is similar to the one on my 12v truck. There’s a high voltage (12 volts) that is active for the first few seconds to help the motor start and a low side (6 volts) that keeps the plugs warm, but won’t melt them.

I bet the high side was active when your starter shorted, and that high side relay was collateral damage. It’s possible they are fused separately, but it seems unlikely to me.

 

[quadrunner91]

What you’ve pictured appears to be an accessory fuse, not a fusible link.

Although not 60 series specific, this thread gives some good info on them.

BJ42 fusible link replacements?

Hi All! I have a 1982 Canadian BJ42 which I'm really enjoying now that I found myself some rear doors and got them mounted ... Thanks to a really helpful guy in Toronto for that! My problem, however, is ... of course ... headlights. Turns out a PO hated the center tap so much that he took it...

forum.ih8mud.com

 

[Greg_B]

this is what I have

View attachment 3900661

That double fuse is stock on the Cdn BJ42 harness. Don't quote me, but I believe that is for the ameter in the dash cluster.

Coming off the positive post of the left side batter (24V side) there should be a fusible link, which supplies the main harness. I've been looking through my photos, but I do not have a clear picture of the factory setup at that post. If I find one I will post it for reference.

Can you post a photo of the harness coming off that positive post; Should be just up the harness from the double fuse.

hth's
gb