Packard Forum Index » V-8 (1955-56)

The '55 Caribbean runs around with it's nose stuck up as it's TL system has stopped working. I've reviewed the post on the Packard Club's web site and it seems to be a fairly through approach. I was wondering if there are any differences between the '55s and '56s that I should be aware before I start the project.

There is a difference in the component layout which affects the way troubleshooting is done. The procedure in the SM differs for the 56 because the terminals and major electrical items are not exposed under the car as they are on the 55s. Mechanically, the load link seats are configured differently so the individual link pieces will not interchange between years

First thing I would do is verify the brake lights are working. If so, when the lights are off do you have 12v measured to ground on the light green wire coming from the brake light switch. That voltage is feeding the under dash TL on/off switch and the TL control switch. The brake switch failing is a common problem and if you don't have 12v to supply the control switch everything stops. The wires connecting to the on/off switch can also get pulled out of the switch accidentally when under dash work is done so check for that possibility too. If the brake light switch proves to be an issue strongly suggest installing one of the kits that replaces the 3 terminal switch with a common and easily available 2 terminal switch and relay.

If the brake lights work check the main TL fuse. The TL motor has an inline fuse located in a red wire near the starter motor which in 55s was a bit underrated and could blow if the motor was toward an extreme limit. If that is OK and there is power to the control switch then time for more extensive troubleshooting. If brake lights do not work or there is no power at all to the brake switch, on 55s check the body feed fuse in the fuse block under the dash.

Here is a full schematic for both systems including the hidden contacts not shown in the regular diagrams so you can see the differences. The 56 drawing has the optional manual control switch drawn in.

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Howard,

Thanks for getting back to me so quickly. In the past, I had problems with brake light switch and replaced it with one of the two terminals switch kits. Also, as a reminder mentioned in an previously post, I changed the car to a negative ground. Will that change anything?

Thanks Marty

Still check the brake light and TL feed circuit even with the 2 terminal switch. There was another poster not too long ago that had one of his kit components fail.

As long as all the TL components are stock items the polarity does not matter. If a solid state rework of the TL control switch has been installed then it might. I have not seen any of the reworked replacement switches or know if they are protected but most solid state items are polarity sensitive and will self destruct if reversed.

Until now, when I did the polarity switch I forgot about the 3 terminal kit I put in. I do know that the TL system worked for months after put it in. I guess that I'll need to remember who I bought it from and check with them.

If the 3 terminal kit does turn out to be the issue and you don't remember where it came from or need another they can be bought from the Pacific NW PAC region or for just a few dollars and some time you could build your own.

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As usual Howard you are a wealth of knowledge and info. I found the for the kit I ordered and have sent them an email. It states fits '55 & '56 so I'm guessing that polarity won't be an issue.

If by the kit you mean the Pacific Northwest Region kit, I'm sure you'll be totally satisfied, there must be hundreds of these in use.

Dave,

Thanks as best as I can remember the kit came from the Pacific Northwest Region. I have an email address and I've asked them if there would be a problem, but have not yet responded.

I have also ordered part to set it up with a relay as above in case it is a problem.

If you already have a kit very doubtful it is polarity sensitive. The only thing I know of that can be added or replaced in the TL system that could be sensitive is the solid state rework of the control switch.

I would suggest checking for 12v coming from the starter solenoid via the inline fuse feeding the solenoids and motor and also the 12v coming from the body feed fuse going to the control switch. Fuses are in both of those circuits and if the fuses are OK the holders have still been known to oxidize and cause problems. Both voltages are checked from under the car on a 55.

The 12v from the starter solenoid and the inline fuse will be on the large copper buss bar nearest the ground which is connected across two of the terminals on the solenoid sides. The 12v from the brake switch will be on the light green wire which I believe is on the middle terminal of the 55 control switch. If the 55 switch has been replaced with the enclosed 56 version you will need to remove the small cover but the voltage is still on the middle terminal inside the enclosure.

If the voltage on the light green wire is missing then time to start troubleshooting with the brake switch and kit but if both voltages are present then something else is going on with the control switch, limit switch or solenoid.