Under Hood Jump Box: How Does This Work?

[AJC]

I have what I presume is a jump box, that is under the hood of my 84 wrecker. I'm having trouble finding info about how it works; since it must serve a purpose vs just running quick connect jumper cables.



I need to draw a wiring diagram to help figure it out. It has two 12 volt batteries in series going to one solenoid and a 6 volt battery going to a solenoid on the other side. The 6 volt battery is kind of throwing me for a loop. Hopefully someone has seen one before to clue me in on how they work. Thanks

[mongocanfly]

Never seen anything like it....any numbers or name on it?

[AJC]

Not on the top or the sides. I should pull the top and see if there are any numbers inside. I know there is a light bulb inside of it that turns on with the key. Which it must be using as a load of some sort.

[mongocanfly]

Something about it makes me wonder if it's a jump box or not..
Could it be part of the wrecker part of your truck?
That 12v and 6v battery sounds strange

[kwmech]

I believe that is the control box for the flashing/emergency lights

[Dead Parrot]

Don't see any cables that look heavy enough to be jumper cable rated. I do see two switches and a fuse holder. Given the various batteries, could be a voltage converter to keep everything charged.

Two 12v batteries in series will give the 24V a lot of heavy duty vehicles need to start. The 6V battery could be to jump the odd ball old vehicle that is still 6V. Both are something a general purpose wrecker would need.

[AJC]

Originally Posted by Dead Parrot

Don't see any cables that look heavy enough to be jumper cable rated.

There are two continuous duty solenoid on the core support. In this photo you can see the jumper cables on the front of the truck that go to the solenoids and a box with a button that activates them.



I will be at the truck tomorrow and will get more pictures of how it connects.

[ACS]

It looks like a charge controller. Charges 12 or 6 volt batteries depending what you select, and can flip between the alternator charging or regular 110 household.