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After 4years of owning the car I have just come across a strange electrical happening.What I have is this.

1. When I switch the lights on to any position everything works fine except the rear lights and stop light bulbs all come on together.

2.When the lights are all off and the footbrakes are applied the tail lights and stop light bulbs all come on together.

3. When the cars gear lever is placed in reverse the backing lights and stop light bulbs all come on together plus the dash lights come on.

4. When the lights are turned on and the foot brake applied of course no stop lights show as the bulbs are already lit.

I have studied the wiring diagram and I can't see anything obvious to cause this oddity.

All that has been done recently is the contacts cleaned on the back up switch which entailed nothing but cleaning with no wires disturbed

Has anyone out there come across this happening and where do I start to look for the fault?

I am hoping someone has an answer

Many thanks

Terry

Probably a bad ground. Check BODY to engine AND/or BODY to frame ground strap. Possible that tail lite housings have poor ground. Maybe problem at rear lite sockets. Mite have bulbs with either staggered or parallel retainer tits that are mis matched/modified to fit parallel or staggerd sockets respectively.

The Stops comming on with tails is an indication that stop is trying to ground back thru tail or visa versa due to poor ground at lite housings to body.

Could be turn signal switch problem.

Thanks for the reply PackardV8.

All the ground straps are good and clean and the tail light housings have not been tampered with in any way nor the light sockets. The lights come on full bright ness not like a bad ground would cause which is with a dim effect on one or the other. The turn signal switch is an add on feature with a separate wiring loom independent of the light circuit.

Terry

Thinking back to a little issue I had with brake lights a while back, not the same as your condition, try something simple. The taillights mount with studs that go thru the fender and then thru the mud shield to the inner fender; clean off one of the studs at each lamp and just put a little jumper from there to a good clean ground, and give it a try. I had been thru some real muddy roads on a tour and the brake lights acted up, never did check the dash lights. Worth a try in any case.

Owen gives good advice in post #4 above. I'm not familiar with the 34 Packard. Are the stop/tail bulbs dual filiment bulbs???? i.e. stop and tail all in one bulb???

Dear Traum:

I think a good place to start is by dividing the circuit.

To do that remove both tail light bulbs, turn on the park lights and check the source voltage with a test light. If both pins have voltage then you have a harness problem.

Move on to the backup light switch and brake light switch. Check both for voltage before and after the switch. If the test light indicates voltage on both sides, disconnect the wires and check for voltage. If you have voltage on both sides then you have a harness problem. Otherwise test the switch for a closed circuit.

Move up to the headlight switch. Isolate the park light post and check for voltage. Disconnect the wire and check the brake lights. If everything is haywire then look for a harness problem.

Grounds are easy to check. Make up a long jumper wire and run it from the battery ground post. With the park lights on use a voltmeter check the voltage between the ground post and the lamp socket base (ground). If you have more than .4 volts (.2 ideally) you have a ground problem.

Finally, with the lights on get under the car and wiggle the wires from front to back. If the lights start flickering then you have found the harness problem. Tip: Put a stand up mirror in your line of vision the shows the action at the back of the car.

As well consider a disconnect switch if not already installed. If the car manages to catch fire it will burn to a cinder.

I'm not familiar with the 34 Packard. Are the stop/tail bulbs dual filiment bulbs???? i.e. stop and tail all in one bulb???

Two separate single-filament bulbs in each tail light housing.

Well Guy's did most of the checks suggested today with no luck. The ground reading came out at 0.1 and the test lamp showed power at both lamp bulb contacts. I did'nt do the lamp switch test as I know the cables in there are a bit mumified. The stop light and back up switches checked out OK.
I believe that the fault is in the harness itself somewhere but I have decided to invest in a new harness for safety sake as the harness is starting to break up in many places. I would hate to lose my Packard though fire. Thanks to all who contributed the possible solutions. I especially like Tims breakdown of the problem into small understandable pieces of info.

Terry