Re: Resurrecting my 56’ Patrician
Posted by HH56 On 2023/7/16 18:20:48
The pressure switch is a round can like item down on the drivers side of the transmission about midway to the rear of the case. It is normally closed but when car starts moving and governor pressure exceeds a certain amount it opens cutting off power to the P,N, and R buttons. It is a safeguard so you cannot accidentally shift into one of those gears going down the road at any speed over a few mph. If those 3 PBs are not functioning, the pressure switch could be bad or a wire could be disconnected at the switch. There could also be a terminal pushed out and not making contact at the plastic plug under the dash.
The control relay was eliminated in very early production. All it did was connect the two feed wires going to the push buttons to power so in effect it was an on/off switch so trans could not be shifted unless the ign switch was on. When they added the automatic park relay they powered that relay from the ign switch directly by running a wire over to the ballast resistor and connecting to the terminal from ign sw feeding the resistor. Someone realized they could do the same on/off function the control relay was doing by connecting the pushbutton wires directly to the ign sw via the autopark relay energize wire. The ign switch now controlled the PBs without the need for another relay. There was a bulletin soon after advising dealers to remove he control relay and send it back to the factory. Some cars never had that done so there are a few control relays still out there.
There is an Autolite service manual on the pushbutton shift in the literature archive. It is an early manual and the drawings show the control relay. Here is a diagram I modified based on the one from the manual still showing all the switches and relay contacts but without the control relay. The other drawing has the autopark relay removed.
Attach file:
PB autopark 2.jpg (171.71 KB)
PB autopark removed.jpg (155.90 KB)
The control relay was eliminated in very early production. All it did was connect the two feed wires going to the push buttons to power so in effect it was an on/off switch so trans could not be shifted unless the ign switch was on. When they added the automatic park relay they powered that relay from the ign switch directly by running a wire over to the ballast resistor and connecting to the terminal from ign sw feeding the resistor. Someone realized they could do the same on/off function the control relay was doing by connecting the pushbutton wires directly to the ign sw via the autopark relay energize wire. The ign switch now controlled the PBs without the need for another relay. There was a bulletin soon after advising dealers to remove he control relay and send it back to the factory. Some cars never had that done so there are a few control relays still out there.
There is an Autolite service manual on the pushbutton shift in the literature archive. It is an early manual and the drawings show the control relay. Here is a diagram I modified based on the one from the manual still showing all the switches and relay contacts but without the control relay. The other drawing has the autopark relay removed.
Attach file:
PB autopark 2.jpg (171.71 KB)
PB autopark removed.jpg (155.90 KB)
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