Packard Forum Index » V-8 (1955-56)

I got a problem with my Packard, when I put out the key from the ignition and put car on P the automatic parking relay start to make noise till I change the bottom to N or R Or D.
When I start the car in N it doesn’t reacts to push o buttons and don’t change the gear to Drive or Reverse.
Help please where should I look and what should I check
The pushbutton mechanism it’s new and all connections are in their places.
On scheme I got positive on A (Green) and B (TAN) should it be like that?

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When you say the pushbutton mechanism is new, do you men only the actuator at the transmission or the pushbuttons inside or both? What exactly is new. Was it working before and suddenly started doing this or did it start as soon as the new mechanism was installed and tried for the first time.

If wires to relays were disconnected use this full electrical diagram to check the wires at the terminals circled in red at the auto park relay. The green wire should be on end terminal A but early looms had two yellow wires which could be mixed up at the relay. Make sure those are connected in the right spots. Look at the ballast resistor on the firewall and see if one end has two yellow wires or a yellow and white wire connected to a terminal. If a white wire, you have the later loom and the wire going to terminal F on the front of the autopark relay is rarely a problem but if it has the second yellow wire then check the wire connection carefully. Verify that is the wire going to terminal F at the autopark relay. The other yellow wire is from the pushbutton "P" button and must go to the front terminal A on the relay.

If the wires are hooked up properly then the problem is somewhere else and more troubleshooting is required. Start by removing the tan and yellow wires from front terminals B and A on the auto park relay. Just let them hang disconnected but make sue they don't short to anything. Pushbutton position Park will not work with the wires disconnected but everything else should. If it starts to work in all positions but park with the wires disconnected, a problem in the auto park relay is a good possibility. I had a similar symptom and found a piece of plastic had broken off inside the relay and jammed the contacts but expect that is a rare occurrence and am not saying it could be your problem. Let us know what happens before any more suggestions are made.

Hello, thank you for your help.
So the cables that go to the button mechanism were fixed by soldering new ones, they had a short circuit between orange and grey.
After I did this, the relay started to work properly and the cables stopped heating between them. The next step was to see why car wasn’t starting on. (It was solved just putting a cable in a good contact with pressure switch)
And after all these operations, car started but don’t turn on any gear except N (as it was in the beginning)
I will put some pictures of the cables and wiring on the automatic park relay now

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Automatic park relay

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It is a sad fact but if the wires got hot enough to melt in one place they could in another place too. You will need to absolutely verify no shorts anywhere else and each button and corresponding finger in the actuator is independent and power is reaching the buss bar feeds to all the buttons. Since something shorted and wires managed to heat and melt insulation I presume the added 9 amp fuse called for in bulletin 56T-25 field mod was not installed? One thing I am not clear on is when you said the other buttons do nothing. Do you mean they are totally dead as in not powered or do they also make things click but nothing happens to change a gear. If they are totally dead I would look for more damaged wiring or possibly some of the terminals at the plastic plugs were pushed out of contact.

Basic operation is the yellow or white wire coming from the ignition switch via the connection at the ballast resistor powers the pushbuttons, fingers, and relays part of the circuit. Originally before TB-25 there was no fuse protection at all in that part of the circuit because the circuit breaker only protects and powers the motor. Power from ign sw into terminal F at the auto park relay powers the relay coil as well as being used as a tie point for providing power to the buttons. In early looms that is done via an orange wire only also connected to the F terminal which goes to the pressure switch and back up to feed P, N, and R buttons. A red/white wire was spliced to the orange wire inside the loom before the pressure switch and goes directly to the pushbuttons to feed the H, D and L buttons. Later looms eliminated the splice and brought both the orange and red/white wires directly to the F terminal to get power.

In operation, when key is on you push a button and power is fed directly to an actuator finger which, depending on where the segment is positioned, sends that voltage via a part of the segment on to one of the shift relay coils to power the motor in the direction it needs to go to move the open part between the segments to the point where it lines up with the powered finger and breaks the connection. That break stops the motor at that gear. All buttons work the same except P, N, and R are locked out while driving over 5 mph by the pressure switch opening due to governor pressure. Those 3 buttons also have an extra contact and wire out. P and N use the extra contacts and wire to power the start relay, R used the extra to powers the reverse lights.

Park is slightly different in the wiring going to the finger because of the auto park relay in the path. When key is on the relay is energized so yellow wire from button on the normally open contact of the relay and tan wire coming from the finger on the common contact are connected in the relay and button works just as all the other buttons as long as the key is on. When you turn the key off the autopark relay relaxes and because 12v via the green wire is always going to the normally closed contact in the relay, that 12v now connects to the tan park finger wire to the actuator causing the actuator to want to move to the park position. Since ign switch is off, power is cut to all the other buttons so it doesn't matter if one of them is still pushed. It will go into park because the relay is what is powering the park finger. Everything will stay that way until the ign sw is turned on again.

What I think may be happening is because of another melt or short, miswire, or possibly a jammed autopark relay contact the park finger is always being powered. When you push another button for a different gear that finger wants to power the actuator and it wants to move to select that gear but since the park finger is also still powered as soon as motion occurs the motor tries to move back to park again causing the relays to click as motor rapidly reverses directions. I do suspect the park finger is the culprit but since there were melts and could be possible shorts somewhere else another always hot finger besides park cannot be ruled out.

Okey I will check tomorrow all the wiring that goes from the switch to the module in the gearbox. Maybe I can try to put gears directly? Adding one direct cable to each gear on the module (take one from positive from battery and try to connect it to R or D position and see if the module change the position)
By the way the strange thing that the parking relay start to do a noise when the ignition is off.
I checked today all the wiring on gear switch (in steering column) and two positive are coming to contacts between N. P. R.
And another between L. H. D.

drive.google.com/file/d/1yAze28280Iwmpe_DNS4syob9krGtnroV/view?usp=drivesdk
Look at the video to see and hear the noise that Parking Relay does.

So we have contact coming on the switch and going out of him. But what is happening with the relay? Can you send me please a diagram with more things to check and tell me where should it be a positive contact on the relay with turned on / turned off ignition.
Thank you for all information and your time!!

Will be waiting for your answer.