Resistor bypass questions

[Corvette1974]

Hello.

My M1028 is perfectly stock and was well maintained by the military and a fire department as a brush truck. It has new glowplugs (installed by PO), and I'm replacing the starter relay, the glowplug relay and I'm rebuilding the alternators (the stuff is on order from CUCVelectric). Since I'm doing all of this stuff, I figure I should do the resistor bypass for the GP's.

I have a few questions about it though.

1. What guage wire should I use?
2. Which post on the junction block should I use (if it matters)?

3. I have read and fully understand the theory of operation of the GP module. Will doing this mod affect the module or any part of the system in a negative way (aka the voltage sensor, or any other system)? Are there any drawbacks to the bypass?

4. Should I just disconnect the current wire from the resistor and just tuck it away somewhere?


Like I said, my truck is 100% military issue with no changes or mods to it. I just want to make sure this is ligitimate and wont hurt anything or affect the original functionality (other than making it better) in any way.

Thanks,
Will

 

[cpf240]

When I did mine, I just disconnected the wire between the resistor pack and the GP relay from the resistor pack. I was then able to use a reamer to make the hole in the ring terminal slightly larger so it would fit on the 12v buss terminal.

Just to clean things up, I then removed the resistor pack and the wire between it and the 24v buss.

As for drawbacks, the only one that I consider of any concern would be if you were to use a NATO slave cable to jump start a vehicle that has the resistor bypass mod, as the GPs will not get their 24v feed from the donor vehicle. However, if your batteries are good, just low, then letting the donor vehicle charge the dead vehicle for a little while, and you should be good to go.

If you want, you can just disconnect the wire from the resistor pack at the GP relay and tape it up and tuck it out of the way. Then you can convert back should you need to be jump started via a NATO slave cable.

 

[Corvette1974]

When I did mine, I just disconnected the wire between the resistor pack and the GP relay from the resistor pack. I was then able to use a reamer to make the hole in the ring terminal slightly larger so it would fit on the 12v buss terminal.

Just to clean things up, I then removed the resistor pack and the wire between it and the 24v buss.

As for drawbacks, the only one that I consider of any concern would be if you were to use a NATO slave cable to jump start a vehicle that has the resistor bypass mod, as the GPs will not get their 24v feed from the donor vehicle. However, if your batteries are good, just low, then letting the donor vehicle charge the dead vehicle for a little while, and you should be good to go.

If you want, you can just disconnect the wire from the resistor pack at the GP relay and tape it up and tuck it out of the way. Then you can convert back should you need to be jump started via a NATO slave cable.

Alright thanks a lot. I knew it had something to do with the jumping of it, but I'll just tape up the wire in case I need it. I dont know how frequently I'll be needing a NATO jump lol, but either way I'd like to retain the capability.

One thing, does it matter which post to use on the two post bar?

Will

 

[cpf240]

One terminal is bigger than the other. I used the smaller one, which, on my truck, was closer to the GP relay. As I reused the existing wire and ring terminal, I don't think it could have been reamed out enough to use the larger terminal.

In simple terms, I don't think it matters which of the two terminals you use. There is a brass, I think it is brass - maybe copper, bar connecting the two terminals together.

 

[M1008driver]

1. What guage wire should I use?

I used 8 since the wire from the battery is 8.

2. Which post on the junction block should I use (if it matters)?

I put mine on the same side the battery power comes from. It does not matter. I use the other side for accessories I add.

 

[Corvette1974]

One terminal is bigger than the other. I used the smaller one, which, on my truck, was closer to the GP relay. As I reused the existing wire and ring terminal, I don't think it could have been reamed out enough to use the larger terminal.

In simple terms, I don't think it matters which of the two terminals you use. There is a brass, I think it is brass - maybe copper, bar connecting the two terminals together.

I used 8 since the wire from the battery is 8.



I put mine on the same side the battery power comes from. It does not matter. I use the other side for accessories I add.

Done deal - I'll either use the original wire or just get another 8 guage wire and wire it with that. I'll let you guys know how I make out with it. Once I receive the parts I ordered, the whole starter/GP system will be spot on and mostly brand new.

Thanks,
Will

 

[Thaidonk99]

any pictures of this ?

 

[MarcusOReallyus]

Check this thread, Thaidonk:

http://www.steelsoldiers.com/cucv/63366-glow-plug-pass-help.html


Hey, just noticed you are a neighbor! (Well, almost!) Welcome!

 

[Barrman]

You can still slave start with the resistor by passed.

CUCV electric has a great wiring manual John made up about the glow plug operation to go along with their glow plug card they sell. It brings up the other issue involved with a resistor bypass. The front battery gets worked very hard. It handles all the load of a glow plug heat up and gets the high rate recharge after start up. Plan on rotating the batteries every few months if you want them both to last a long time. No, most people don't do this and can get several years out of the front battery. However, you still need both batteries to start the truck.

 

[Corvette1974]

Alright. I left the system as military stock, no resistor bypass. Everything in the system is new except the controller. It works perfectly and starts no problem every time. For now, stock it is for me. Thanks for the help though.

I cant wait to test it during some cold winter days though.

Will