1950s Power window issues

[Chavez_automotive_systems]

Ok, I'm currently helping a friend with his 1953 Cadillac power windows. They did work when he bought the vehicle but stopped working recently.i tried to troubleshoot the original wire harness but ran into a lot of improper repairs done over the years so we decided to scrap it and build a new harness following the repair manual. We installed a new circuit breaker, all new window switches, and I fabricated a new wire harness per the manual. As soon as we applied battery power, the hydraulic motor turned on but no windows would go up, they all went down no matter which way you hit the switch. Found that the driver rear switch was stuck, I removed the power wire and the switches still would not work properly. Infact they wouldn't turn the hydraulic motor on in the up position. What am I missing? Each wire was routed individually and in their own color code as not to mix anything up. Any suggestions before we just rip everything out and go to aftermarket power windows? Thank you, Jimmy

[PHIL WHYTE CLC 14192]

From memory the way the system works is quite simple, for the windows to go down the solenoid on the specific window needs to be open without the pump running and for the window to go up the solenoid on the specific window needs to be open WITH the pump running. I would guess the pump isn't running in. That would mean that the switches are not activating the pump in the up position (could be a missing live feed to the pump), or the pump is faulty. Try taking a direct live to the pump and try a window in the down position. Phil

[Jeff Rosansky CLC #28373]

I don't know that year, but is there a solonoid on the pump? That could be bad not allowing it to turn on.

[Chavez_automotive_systems]

I don't know that year, but is there a solonoid on the pump? That could be bad not allowing it to turn on.

yes, it has a trash can style solenoid. That's what I'll check tomorrow.

[tluke]

So the battery connects to the pump on the firewall through a solenoid. Coming off that solenoid (upper left corner of diagram) is the main power feed to each switch (B post -for battery) shown in red and labeled 14-16RXT - always-on power. This is the circuit that goes to the B post on each window switch. When you push the switch to raise the window, the B is connected to the M (Motor) post which is the gray (GXT) line that goes back to the what's shown as the top post on the solenoid on the pump thereby energizing the solenoid, thus allowing current to flow to the pump motor. The internals of the window switch are such that pushing the switch to UP not only allows current to the M post but also to the C (CYLinder) post which opens the cylinder inside that particular door allowing fluid to flow in either direction. When pressing UP, the pump also turns on so with the cylinder open, the fluid pushes the window up. When pressing down, the cylinder opens again, no power is sent to the pump and a spring in the window regulator pushes the window down forcing the fluid back to the pump.

That being said, if you push the window switch up and the window still goes down but you hear the motor, the door cylinder is open as it should, power is going to the pump, as it should, but if the pump was actually pumping, the window should go up. With the door cylinder open (which it is in either UP or DOWN) that means the pump is not pumping and the window goes down (BTW, how do you get the window back up?). I assume you've checked the fluid levels in the pump. You might want to flush the fluid. Originally brake fluid was used but some have been converted to power steering fluid so make sure you use the correct fluid ( certainly don't mix them)

 You mentioned that your pump was turning on until you removed the power wire to the driver's side rear switch the motor stopped turning on. That's curious. To check if the motor is getting power, one person pushes a switch up while someone else measures power at the 16GXT terminal on the relay at the pump (on the firewall). If power but no motor activity, either the solenoid or the motor is bad. If no power try jumping the 14RXT post on the solenoid very quickly to the 16GXT post on the solenoid to test the motor. If motor works, it's your wiring from the switches (16GXT) to the solenoid on the pump.

Remember, pushing the switch up should provide power to the door cylinder and the pump then does the work. Pressing it down powers just the door cylinder and the spring does the work. Pressing up with no pump working or pump not really pumping, the window goes down.
(click to enlarge)