Packard Forum Index » V-8 (1955-56)

Howard,,

That's the best way to do it,, i like that,,

riki

I have checked out some of the suggestions and first thing is the PB actuator is not working, it blows a fuse each time I replace it. I guess this is the problem why the starter doesn't do anything as it probably isn't in N or P now I have to find out why it is blowing the fuse. I do have a question about the starter relay and transmission control relay. Are they the same relays? I have read that a GM power window/seat relay is the same relay. Does anyone know if this is true? Thank you.

The control relay and starting relay are the same. If you have a control relay, your car must be very early production.

Is it the fuse from white or yellow wire to the silver relay the one blowing or another one? How many amps? Does it blow as soon as you turn the ignition sw on & it makes no matter which button is pushed at the time or is it OK until you push a button and which one?

If it's the fuse I think, then that feeds some things in addition to the PBs and would be nice to try and narrow it down as to what/when.

Remove push button pod. Inspect electrical contact fingers of pod. These are known to break off or fracture to the extent that contact is not made and therfore no shift of trans. If one of the fingers breaks away completely and falls into the wrong area it can short thus blowing a fuse or tripping the circuit breaker of the PB system.

i'm also bewilldered by the "blows a fuse" statement. I do not see any fuse in the wireing diagram for the PB circuit. Only a circuit breaker.

If the pressure switch (part of the PB circuit) goes bad then engine will not start. See p 118 of Twin Ultramatic section of service manual. IF pressure sw is burned out just disconnect wires from switch and plug them together as a temporary work around.

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" I have read that a GM power window/seat relay is the same relay. "

First time i've heard of it. IT would be nice to know if true even if some modifiction is needed to the relay.

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The fuse I suspect we are talking about is the additional 9 amp first mentioned in bulletin on how to remove the auto park. It was added to protect the fingers and some other items & suggested to be placed on all cars. In original design, power to those was fed directly off ign sw. The breaker "protects" the motor side but as Randy found, even that is not necessarily the case with a self resetting breaker.

To eliminate a lot of wiring, the buttons can be all "unpressed" before turning on the ignition. That way the fuse will only see the auto park relay coil, wires to the pressure sw, and feed side of 3 buttons on one side and the second direct feed to the other 3 buttons on the other wire. If it still blows, then shorted wire, pressure switch, or as you mentioned, a contact is most likely.

To "unpress" the buttons, push one on the same row as the one already pushed but only about half way down until the original button pops up. Pull the button being pushed to release the first one back up before it latches.

Once it's figured out when and what is blowing it then troubleshooting can continue.

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Problem is there were several running changes in the PB circuits and the shop manual only shows ONE version of the possible schematics. It's the one AFTER the park relay was added in production, but BEFORE the control relay was eliminated.

While it is important to consider the owner's manual, followed by the shop manual and parts book, don't forget the supplemental info which can be found through this site's exclusive online Packard Service Index. Topics relevant to the pushbutton control are neatly grouped together in the 1955-56 Index, filed under the Twin Ultramatic category.

More specifically, you should take look at STB 56T-25 that was issued to Zones only (and after production had ceased in Detroit), regarding the elimination of the automatic park function and relay. You'll find that a fuse was added to the white wire, which supplies power to two wires that feed the two buss bars for the pushbuttons.

Blow that fuse and you'll get a no-crank condition, because there won't be any power from the P or N buttons to energize the starter relay. As a result, the circuit from the ignition switch to the starter remains open. This is the same result you'd get with a bad pressure switch.

Blown fuse could be the result of a problem in the actuator, no?

Blown fuse could be the result of a problem in the actuator, no?

It could which is why I suggested the "unpressed" condition so nothing gets power past the two button feed busses & actuator would essentially be dead. Would consider the actuator as a last resort because in an earlier post he said it had been overhauled and had all new wiring. Would hope it was a good job and is still good and nothing was pinched putting it back in.

Think we should rule out the pressure switch circuit first since it's a known failure item. Maybe a wire pulled out of terminal & shorted or switch itself somehow shorted.

Sorry I have been gone all day, the fuse is a 10amp inline probably added when auto park was eliminated I don't remember. I am unable to trace it at this time. I will try some more of the suggestions given and try to get back tomorrow. thanks