Packard Forum Index » V-8 (1955-56)

My wife recently inherited a '56 400 and she loves it. I am getting tasked with maintenance and such. I've got the oil and coolant figured out but I am having problems with the power windows. One would not go down when we got the car. After our ride around town yesterday, two would not go back up. So essentially we are down to 1 working window. I found a post on here by spencer21 that said that the window relay is Delco-Remy 12v-895 and found a picture of where it is in the engine bay, but want to make sure that I am approaching the repair the right way. As a note, the car has some kind of oil leak that needs repaired also and oil is getting sprayed up towards that part of the hood--could that have something to do with it? Any help would be appreciated.

Oil leak

Possible timing cover. Oil seal

Windows.

Could be the switch. I would check that first.

Power windows can be kind of an issue particularly with large glass in 2 door models. Due to the lack of a significant mechanical advantage in the mechanical portions of the door and quarter window regulators, the motors are working at near maximum capacity when raising the heavy door and quarter glass. On the long doors, there is also a twisting action between the motor section and the section that actually raises the glass. That twisting can flex the inner metal door panel resulting in cracks in the metal where the glass raising section bolts to the door.

Since the entire system has not failed, the relay is not the issue. All that does is provide power thru a circuit breaker to the window circuit when the key is turned on. There is a thermal breaker in each motor, but for that to trip, the motor would need to be fairly hot. If there is a mechanical bind and the motor is really straining it is a possibility though. The motors themselves can fail and a typical failure is the shaft breaks inside the motor as the window stops abruptly in the up or down position. Doubt that would have happened on so many motors so another likely issue is the switches.

Except for the drivers door, there are two switches that can work each window. If only one switch fails to move the window but the other does then most likely a bad switch or a connection. If both fail, motor, a loose connection to the motor, or a broken wire is more likely.

The wire connections to the switches are made by a small terminal block that is just pushed onto the pins coming out of the switch. There is no mechanical means to keep it in place so it can be pulled loose by vibration and weight of the wires. The terminals inside the strip can also become loose or corrode, both resultig in a poor connection. Worst case is the switch itself has failed. All the current supplied to the motor goes thru a relatively small contact area in the switch. The heavy current required when the window hits a stop and the brief period motor can no longer move before switch is released can burn the small contact area over time until it finally reaches a point enough has been burned off the connection cannot be made. That almost sounds like what has happened on at least one switch. There are no repair pieces so if you have a bad switch the only solution is find another. You can bypass the switch to test the motor by making a small jumper from decent size wire and insert it into the holes in the terminal block to mimic the switch. From the center hole to either of the outside holes will make the motor move the window up or down.

I would suggest taking the upholstery panels off to get to the switch and mechanical pieces and make sure the terminal is securely on the switch. It will be difficult to do much lubrication but you might try getting some water resistant grease on the slider tracks at the bottom of the glass to take as much stress as possible off the motor. Also check for cracks at the top center portion of the door.

Here is the wiring diagram for the window circuit. This is the 55 drawing and is identical wire wise to 56. I posted this one because it does not show all the extra sedan door lock circuitry which your hardtop does not have and would tend to confuse the issue. The motors are all the same. There are two wires feeding each motor. The motor case is ground and only ONE of the motor wires gets power at a time. Voltage on one wire makes window go up, voltage on the other wire makes it go down.

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Here is how to R&I the power window switch.youtu.be/D17UvV59ju0

Post a picture if it looks burnt up.

Nice video. If someone does have a burned switch and cleaning does not help, often the parts are interchangeable between switches. This can sometimes help if you have bad switches but different parts are the cause. HOWEVER, there is a caveat. Apparently there were different vendors making the switches Packard used. Since 55-6 switches all look and fit in the housings the same way it is unknown if the difference was by year or if each supplier furnished switches as needed and the stockroom guys just replenished the production line using whatever was in stock.

Another poster found that in the case of the 4 switch drivers door assy, there was enough difference the parts would not interchange with another switch he had. He did not mention if the single switches have the same issue but it would not be a surprise if this is the case.

When I did mine used a little dielectric grease on contact area hoping to prevent corrosion and add a little smoothness to operation. Cleaned the plastic parts and the three pin connectors on switch to help with endure good connection Have some pictures of front drivers switch with different contacts will have to locate them. The two switches are the same except for the buttons and color of the contacts. Have been told Cadillac switch is same as Packard may be the one with ribs on switch is. The switches on Caribbean are smooth but Randy had one with ribs marked for use in Caribbean after looking at it the plug in connectors are in better shape

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G'day Sheafurby,
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I invite you to include your '56 Four Hundred Coupe in PackardInfo's Packard Vehicle Registry.