'64 W500 Wiring Cleanup (Fire Truck)

[W_A_Watson_II]

OK, I've started the process of cleaning up the wiring on my 1964 W500 Power Wagon Fire Truck. I've used MoparNorm's wiring schematics and have figured out the dash connectors, including the Accessory Connector.



There was apparently a low oil pressure shut off setup on the truck at one time, but the dash side connections have been cut/removed. The truck's electrical system and load was changed by Maxim Fire Truck Company, and it's running a larger output Delco 10SI Alternator, and running 8ga wire. I've found plenty of bad wiring on the truck, and want to make sure it's safe.

I've got an extra relay under the starter relay, that looks to have been part of it, but I'm not 100% positive. The Relay looks to be Dodge Factory based on the attachment and wiring. One wire was connected to the oil pressure switch. In the following picture you can see the relay, what do you think? It appears to only energized during the cranking process.



Thanks,
Will
My DODGE TRUCKS

[W_A_Watson_II]

(CONTINUED)

I've got a lot of engine and some dash side wires to replace and cleanup. I've found a few in-line fuses, and circuit breakers, along with a glass fuse buss on the engine side firewall. I'll add a main line fuse, and fuse block for the added lights, etc. Anyone with suggestions or recommendations?

Oh, the one thing I know I need to do is get rid of the Amp Gauge. The Fire Company had already replaced the stock 10ga main wire with what looks to be a 8ga wire, but still running through the Amp Gauge. I'll do the Amp Gauge Elimination and install a Volt Gauge as part of the job. However with the stock Amp and Fuel gauges being a combined gauge, that will mean replacing the Fuel Level Gauge as well. I'll probably start with out replacing any gauges, as after looking at the dash again, I should probably replace the oil and temperature at the same time to keep it looking decent. My dash is the 6 round gauge with Tach.

I did learn something today. While doing some wiring cleanup and investigation, something other than a lot of bad and dangerous wiring I found a strange connection. The truck has the 6 gauge dash with electronic Tachometer, and I found the added signal wire connected to the coil on the distributor side. Then I found that the coil "+" wire in the stock harness did not go to the coil. It was attached to an added wire by the Maxim Fire Company that ran back with the wires to the rear of the truck. A wire running back in the same bundle was attached to the coil "+" side.

So I wondered if I'd missed a manual kill switch on the Fire Bed. So I took another look and could not find any. I continued to clean up the wiring. I found the oil pressure wire but I didn't find an additional Tachometer signal wire running to the Fire Bed Tachometer.

The Faria Tachometer on the Fire Bed worked, so I started some research. It turns out that Faria is a Series Tachometer! Hadn't ever thought about how the older Tachometers worked, but now I know.

I'm down to three unknown wires, and I suspect one is the Power feed for the Hour Meter and Oil Pressure Gauge, while the other two were for the hose real motors.

Thanks,
Will
My DODGE TRUCKS

[Tom Petroff]

Nice job Will.
It's hard to help with wiring without seeing it myself.
But remember the oil Pressure switch most often completes a ground circuit.

So with that said it may not necessarily be a shut down switch unless the relay it grounds to activate, has Ign. wires on it.

Most of the time a oil switch would energize a fuel pump.

And the proper way to use a hour meter is to run power to it and complete the ground through a oil sender so you get actual running hours.
TGP

[W_A_Watson_II]

Tom,

Thanks, I'll have to see how the relay was wired. The truck was converted to an electronic pump later in life, so if this was a Dodge Factory setup, it would have to effect the ignition some how, but I'll never know.

The Truck has a mechanical and electrical oil pressure gauges, and the oil pressure switch. Once I get the wiring done, I'll have to check and see if the switch has gone bad.

As for the hour meter on the Fire Bed, other than the Tach/coli+ loop, there was only power leads going back.. So it might be connected to the Tach Loop for power, but the other oil pressure switch wire ran into the dash with the other relay wire.

Isn't it fun chasing years of botched wiring.

[Ron in Indiana]

Will, better thee than me on your wiring. I'll stick to pounding dents, fixing rust and spraying primer. Hope it all works out. My son spent 8 hours sorting out fire house wiring on Andrew's Miss Eudora mini pumper. Good luck

[W_A_Watson_II]

Ron, I'd much rather do the wiring than the de-denting and painting. On this truck, all the extra Fire Wiring is the fun part. Wiring the truck I could do quickly and easy, but all the added and changed wires make it fun. It would be easier to rip it all out and start over, but all the original un-botched wire is in great shape. Maybe we should have lived closer together we might make a great team.

[greg rider]

Tom,

Thanks, I'll have to see how the relay was wired. The truck was converted to an electronic pump later in life, so if this was a Dodge Factory setup, it would have to effect the ignition some how, but I'll never know.

The Truck has a mechanical and electrical oil pressure gauges, and the oil pressure switch. Once I get the wiring done, I'll have to check and see if the switch has gone bad.

As for the hour meter on the Fire Bed, other than the Tach/coli+ loop, there was only power leads going back.. So it might be connected to the Tach Loop for power, but the other oil pressure switch wire ran into the dash with the other relay wire.

Isn't it fun chasing years of botched wiring.

The pump panel may have had a second tach added so the pump operator could see it.

That odd coil wire could have been an emergency shutdown in case of an overspeed.

The relay could be for the fuel pump with it running through the oil pressure switch. That would shut off the fuel pump if the engine died for whatever reason. All newer fuel injected vehicle have this feature in case of a crash so it doesn't feed a fire.

I may have cleared some things for you or made them muddier. The fire department I was on had some older gas trucks and only a few of us took the time to work on them. Newer kids wanted newer trucks,,fools.

[Gordon Maney]

I like the "HORN" on the steering wheel spokes.

[W_A_Watson_II]

Thanks Gordon. I washed it off with some thinner, and the shellack was still under it, and it only on the wheel, so it was there for several years. You have to wonder who was driving that didn't know where the horn was.