My F250 came with the auxiliary battery option. Over the years it has been sort of butchered so that now it has most of the wiring, a couple of solenoids and relays and a lot of loose ends of wires.

First, how did it work and what was it supposed to do? Secondly, anybody have a wiring diagram or two, that would help me put all of this back to stock?

We have started a lot of work on the truck and I want to make sure that we are doing things correctly.

Thanks in advance for any help,

Eric

 

1973/79 Ford Light Truck Parts Catalog / Illustration Section 145, Page 10: 1973/79 F100/350 DUAL BATTERY WIRING & RELAY INSTALLATION

Ask FTE member mikeo0o0o0 (has this catalog on a CD), to scan and post the above.

This CD catalog is available from hipoparts.com for about 22 bucks.

I cannot scan & post, because my catalog is on Ford microfiche slides.

 

Bill, thats great info already. Thanks a lot and man, don't you ever sleep? I have a friend who is a Ford Dealer and I will just call him to get his Parts guys to scan that info for me and send it to me if Mike can't.

I just have to wait a few hours as usually people on the West Coast are asleep right now, especially retired ones, LOL.

Thanks a lot.

Eric

 

Except Bill, he never sleeps.
Here's the illustration for you.
Click on the .pdf link to view.

 

Also, the way this worked was actually pretty simple.
The purpose of the second battery was to be able to power a camper without having to worry about running down the truck's battery.
The system consists mainly of the second battery, solenoid and associated wiring.
When the ignition switch is "off" the auxilliary batery is completely disconected from the electrical system. You can power your camper and completely run this battery down without fear of killing the main battery. After you start the truck the aux. solenoid by the second battery closes and the alternator will recharge the battery while you drive.
Some people think the aux battery is the equivalent of a bigger battery for starting. It doesn't have anything to do with starting or powering the trucks electrical system and, unless you have a camper or something else that needs 12V power, really kinda useless.

 

Perfect information. Thanks a lot and I do have a need for a second battery in this way of setting it up. I haul around a race car trailer and this would be great for the electric winch and assorted lights, inverters, etc.... This will mean that I don't have to keep running the truck while I use those things.

I had better make this battery a big one with lots of capacity, . Maybe I will put a power station in the back of the truck to run all the various cordless tool battery chargers off of.

Thanks a bunch to both of you. I just hope it all works when we hook it back up. I guess Bill is sort of like Batman, just sitting and waiting at all times for a cry of "HELP"!

Eric