24v to 12v lessons - 80’ BJ41

[mginn68]

Morning -

Seeking for lessons learned on converting a 80’ BJ41 from 24v to 12v ? Plans are to put in a 3B from an 85’ cruiser and convert to 12v. Has anyone been through this adventure ?

Assuming at a min these items will have to be changed - wiper motor, fuel sending unit?

 

[ceylonfj40nut]

Morning -

Seeking for lessons learned on converting a 80’ BJ41 from 24v to 12v ? Plans are to put in a 3B from an 85’ cruiser and convert to 12v. Has anyone been through this adventure ?

Assuming at a min these items will have to be changed - wiper motor, fuel sending unit?

Starter, alternator, EDIC, glow plugs, need to be 12v

 

[mginn68]

I'm using the EZ Wiring 21 Standard Wiring Harness for this. I'm working one circuit at a time. Headlights, taillights, and blinkers are done and working. I haven't tackled the brake lights yet. Next on the list is the reverse backup lights. I know I will have to hook this to the switch on the tail of the H55 - 5 speed. Any advice on which circuit or wire to use? Thanks!

 

[george_tlc]

An idea of what is ahead - it's my oz diesel patrol that was stock 24V that I converted to 12V. Nissan initially released the mq patrol as a 24V vehicle, but a few years later dropped 24V and went 12V. I had a donor POS that a grabbed lots of bits off to convert my patrol. It took several weeks of long days. Totally worth it!

If you are interested -> MQ 24V to 12V retrofit - https://george4wd.taskled.com/mq2412.html

It details pretty well all the things that needed doing. Lots of 'surprises' to deal with too. Funny one was the cabin fan didn't seem to blow air - turns out nissan flipped the polarity of the wires to the connector (from the 24V model to the 12V model) - just needed re-pinning.

Fusible links will need to be 'resized' for the higher currents that the wiring will see at 12V vs 24V. Had a fusible link give up the ghost several hundred miles into the western oz desert with temps up in the 40C+ range. Replaced it with some stranded wire with a guesstimate of the number of strands to deal with. Also had to replace a bunch of fuses in the cab to also deal with the higher currents.

Lots of little details to keep you busy

cheers,
george.

 

[mginn68]

An idea of what is ahead - it's my oz diesel patrol that was stock 24V that I converted to 12V. Nissan initially released the mq patrol as a 24V vehicle, but a few years later dropped 24V and went 12V. I had a donor POS that a grabbed lots of bits off to convert my patrol. It took several weeks of long days. Totally worth it!

If you are interested -> MQ 24V to 12V retrofit - https://george4wd.taskled.com/mq2412.html

It details pretty well all the things that needed doing. Lots of 'surprises' to deal with too. Funny one was the cabin fan didn't seem to blow air - turns out nissan flipped the polarity of the wires to the connector (from the 24V model to the 12V model) - just needed re-pinning.

Fusible links will need to be 'resized' for the higher currents that the wiring will see at 12V vs 24V. Had a fusible link give up the ghost several hundred miles into the western oz desert with temps up in the 40C+ range. Replaced it with some stranded wire with a guesstimate of the number of strands to deal with. Also had to replace a bunch of fuses in the cab to also deal with the higher currents.

Lots of little details to keep you busy

cheers,
george.

Hey George - great write up...that was some major work. Yeah, I have a pretty step climb ahead also. I'm just going to take one circuit at a time. I'm searching for someone who has been on the path in the past. Surely someone has...Have a great day!

 

[mginn68]

Does anyone have an understanding of a 24v instrument cluster? I assume the lights are 24v or I believe I see a resistor that could step the voltage down? Trying to decide if it's better to buy a new digital cluster vs going through rewiring this one from 24v to 12v. Thanks for any help!

 

[mginn68]

I'm continuing to work through this conversion. Working on the charging system now. Does anyone have a recommendation for a 12V alternator and voltage regulator (3B diesel)? I've read on some going to a GM one wire alternator, but I would still need a vacuum pump for my brakes.