Circuit Breakers

[Madriver1968]

I've done a lot of reading on the forum about circuit breakers and the reasoning behind the decision not to include them in the M38A1 design.

My question is this -- have folks added M38 circuit breakers to their M38A1s?

Thanks!

B.

[wesk]

I am a firm believer in circuit protection. Especially when we want to protect our investment in these 24 volt jeeps. 24V makes a bigger smoke cloud very much faster than a 12 volt system. At over $700 a harness whay would anyone not protect their wiring and their jeep?

If you look up Klixon they are still in the same Circuit Protection business today. Just purchase the appropriate rated CB's and insert them in each circuit. Their parent company today is Sensata - Klixon subsidiary.
http://klixon.com/klixon/circuit-breake ... l-9115.htm

Here's the Catalog you want: http://www.sensata.com/download/klixon- ... atalog.pdf

If you have any of the post bendix light switches then you already have a built in lighting system CB in the switch. So you can ignore lighting and just take care of the other circuits.

A battery cut-off switch is a very good device to add while you are at it.

[Madriver1968]

Thanks so much again, Wes! I really appreciate it. I already installed a battery cut off switch -- growing up around old cars, that was the first thing I did when I brought the Willys home.

Do you happen to have suggestions about where to install circuit breakers and what rating? Any additional wisdom is most appreciated.

Again, thanks.

[wesk]

If your circuits are all stock just use the early M38 wiring diagram with the CB's.


You just get one of these mount brackets off an old M38 cowl battery box or fabricate one just like it and install it on the driver's side of your M38A1 cowl battery box.


Then add the 3 CB's. It's very difficult to get original Douglas metal shell connector CB's but the Packard rubber shells are easy to adapt.

[Hawkshadow]

Original:


The mount that I made out of some sheet with nuts welded to the rear for mounting the breakers.


The whole unit mounted in place with NOS breakers.

[4x4M38]

Very nice Jordan.

[Madriver1968]

Thanks again guys. I appreciate it!

[Madriver1968]

Hi guys,

I'm getting ready to install the circuit breakers on my M38A1, and I've run into another question. My wiring harness has a wire, marked 11, that according to the wiring diagrams in TM 9-8014 is connected to the ignition switch. However, in reviewing wiring diagrams for the M38, I see that wire 11 runs from the ignition switch to the first breaker, and then from the first breaker to the second, and from the second to the third.

For my M38A1 wiring harness, do I simply ignore the wire marked 11, and put a bag around it with a zip tie?

Thanks!

B.

[wesk]

I showed #10 going all the way across to the switch which is out of site because 10 supplies power to the three CB's and the ignition switch. It becomes #11 at the switch pig tail that is marked 11.

Wire 11 provides power to your ignition switch for wire #12 that powers the coil. You must connect 11 to the end of 10.


In this early m38 diagram wire # 11 is simply picking up power at the last CB that wire #10 supplied with power.

Something else for you to think about is that center CB is for the light switch power feed. The old early M38 light switches did not have a built in CB. The later switches all do so you can actually use that 15 amp CB for another accessory.

You must realize that the individual system wiring diagrams do not show all the wires that connect to those CB's.


This one shows wire # 15 going from the center CB to the light switch.

What you will actually end up with is:



Wire # 10 going to a dual connector to feed both wire # 11 at the ignition switch and wire # 15 to the main light switch.

[Z]

Is the wire connecting the breaker or any wires to/from the breaker larger AWG than #14 wire? Thanks!