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This switch underneath a 34 1101 does what, it is located just below where the brake assembly moves when the brake pedal is depressed, to the rear of the battery underneath I know two wires run to it one for the brake lights and the other I am not sure. What does this switch do as I think that is where my short in the car is. Can it go bad and cause a short showing up on the amp gauge.

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It's your stop light switch. They are extremely rugged but like anything, a failure, though remote, is always possible. You can service it easily, just remove it for testing. Very easily disassembled for service if needed. Yes, if you have a short in the brake light circuit it will show on the ammeter, as will a short almost anywhere in your electrical system. Is your short only occurring when you apply the brakes?

Your brake light bulbs are also activated as "backing lights", using some of the same circuitry, via a switch on the rear of the transmission. The wiring is quite clearly shown on wiring diagrams available on The Packard Club website, in the 33-36 parts list available on this site, and elsewhere.

If you need those large oversize glass fuses, they are available from NAPA as an exact duplicate of the originals, #782-1017 for 20 amp, 782-1019 for 30 amp.

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No the short occurs when I turn on my cut off relay. But when I sometimes step on the brake and remove the wires from the brake switch and then hook them back up the short does not occur. Also my back up brake lights do not come on when I back up or even put the transmission in reverse with the engine not running like they use too.

Today I checked out the brake switch is seem to be ok, but when I hook all the wires to it the brake lights do come on even when the brake pedal is not depressed. Looked at the brake linkage down there and it is not touching the switch when not engaged. Also disconnected the wires and there still is a short as the amp gauge is showing a discharge, but when all the wires are hooked to the brake switch is shows more of a discharge due to the brake lights being on.
So then disconnected the wires from the transmission brake switch and they made no difference in discharge on the amp gauge.
Moved around all wires under the car and under the hood but made no difference in the discharge of the short trying to find it. So right now am at a loss of finding any thing. Looking for ideas any help would be great

1. If your brake lights are on with the brake linkage not contacting the switch and the transmission not in reverse, most likely one switch or the other is faulty. Simple process of elimination should tell you which.

2. When you have this "short", do we assume the ammeter shows a full maximum discharge and then a fuse blows? If not, why do you think you have a short?

Good point, Dave... it could just be registering 'consumption'

Both switches checked out ok and the short was still occuring as a slight discharge on the amp gauge. So took it for a drive as I remember the short occurring when the gas tank has just been filled up and after driving for a while sure enough the short was no more guess due to a lower fuel level.

So now am sure the short is in the sending unit for the gas gauge. Does one have to drop the tank to get at the sending unit and has anyone had a short occurring with the tank full only, could it be with the float resting to high up and shorting out. Any ideas on this. thanks for all you help in this.

A "slight discharge" is typically not a short circuit, a short would be a full deflection of the ammeter and a blown fuse or tripped circuit breaker (headlight circuit). You likely have some sort of resistance problem with your sending unit. You'll have to drop the tank to remove it. They can often be repaired by places like Wolf Instruments, also repro units might still be available from Atwater Kent. If your existing unit is repairable, I'd go that route rather than the repro unit.

Hardest part of dropping the tank will be dealing with the flexible link to the filler neck in the taillight. The original brass bellows has probably been replaced with an improvisation of some sort. Note that the tank is not held in place by the usual type of strap; drain it and use a hydraulic jack with a large piece of wood between the tank and jack. Unbolt the tank, disconnect the fuel line and sending unit wire, and lower away. Note that the tank is internally baffled into multiple (6?) compartments which can complicate things if you choose to have the tank coated.