Ok, I'm going to assume that the Fire Department changed to a 12V system which means that the starter has been swapped to a 12V one. To hook up the batteries properly for a 12V system instead of a 24V system, do the following:
1) With no cables attached to the batteries make an interconnection cable that goes from the front battery positive to the rear battery positive and then from the rear battery positive to the top of the big junction block on the firewall. Make sure the 8 gauge wire that runs to the small junction block above the master cylinder is attached to this cable.
2) Connect the rear battery negative to the bottom of the big junction block on the firewall
3) Connect the front battery negative to the frame.
That should get you 12V to all systems.
To change back to the stock 24V system, you will need:
The missing alternator replaced and connected properly
The starter replaced with a 24V one
The glow plug resistors (which is actually listed as Battery Booster Resistor in the -34P for some reason) hooked back up
Then you hook the batteries up like this:
1) With nothing hooked up, connect the rear battery positive to the top of the big junction block on the firewall
2) Make an interconnection cable that goes from the rear battery negative to the front battery positive. The 8GA wire that runs to the small junction block above the master cylinder attaches here.
3) Connect the front battery negative to the frame.
This will give you 24V to the big junction block on the firewall and 12V to the small junction block above the master cylinder.
You said that the engine cranks slowly and then stops, correct? You can try to hit it with 24V and see if they just scavanged one alternator before releasing it, leaving a 24V starter, and see if that makes a difference. If not, you will need a 24V starter to go back to 24V.
On the Alternator issue, is the mounting hardware and wiring still present for the missing alternator? If so, you can order the correct one from OD Iron and then bolt it on. If not, please describe the condition of the wiring leading to the missing alternator (cut off, taped up to the harness, etc)
The missing Glow Plug Relay (GPR) can be replaced with a GPR from a 1996 Ford F350 with a Powerstroke Diesel. Bolt it to the firewall beside the master cylinder and hook up the wiring as follows:
1) Connect the 8GA wire from the GP resistor to one of the large terminals on the GPR, the other side of the GP Resistors should go to the big terminal block on the firewall. If the system is 12V, not 24V, connect this wire to the small terminal block next to the master cylinder instead of to the GP Resistor.
2) Connect the wiring from the glow plugs (should be two sets of 4 green wires connected together with a larger orange wire and a large ring terminal) to the other large terminal
3) Connect the small orange wire with a large ring terminal to the same large terminal as the glow plugs (Important step)
4) Connect the light blue and the pink wires to the two small terminals. Doesn't matter which is which.
If everything is hooked up properly, the Wait light should come on when the key is on and you should hear the clunk of the relay as the light comes on and goes off.
Let us know how it goes.
Later,
Joe
