Original circuit breaker

So how does the original circuit breaker/terminal strip work on these trucks? Is it a timed delay reset breaker?
Wasn't sure what is in the block behind each set of terminals.

They're self resetting. I believe it's a bi-metallic strip that heats up as the load increases until the circuit is broken. Once the strip cools the circuit will close. Can't give you a time frame- it'll be what it will be. Could be moments to minutes- not sure.

Thanks Jake. I decided to run my truck on the 6 volt system for awhile since all the components still work. I will upgrade the wiring then switch to 12v at a later date. I did not see a current rating on the breakers or in the service manual. I may have to look closer at them.

They should be marked on them how many amps. You can still get them rated for 12V, not sure about 6V but I believe you can use PIE formula to convert (Power = Intensity or Amps Times Electromotive Force or Volts)
http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Circuit-Breaker-20-Amp-Threaded-Stud/_/R-BK_7823106_0361088603

With CB and fuses amp is amp regardless of voltage. Voltage come into play on how much the CB can safely interupt without "flash over" of the contacts. With the voltages were talking about here (7.1 max on a "6 volt system or 14.2 on a 12 volt) voltage doesn't realy matter. I wouldn't try and use an automtive breaker on house current, but they should be good for 6,12 or 24 volt systems. The current required for the device being proteted will be less on a 12 volt system then a 6 volt, all other things be equal. So wipers for example, should use a smaller CB on 12 volt system then when 6 volt wipers are used.