Select a Vehicle

Find parts for your specific vehicle

Choose your Vehicle

Having trouble finding a specific product?

1969 Mark III Power Window Issues

Hi Bill,
I’ve consulted you before and your advice was a Godsend so here I am again! On my 1969 Mark, I am trying to get all power windows working. I know every motor works, but controlling them is a different story.
Here’s the current situation: I can only open and close both front windows, and only from the drivers side switch panel. The switches on the front left panel will not open the rear windows, nor do the rear switches work. I can say for certain that the wiring has been tampered with by a prior owner, but to what extent, I’m unsure. When I purchased the vehicle, everything worked. Magically, now it doesn’t.
So I consult my wiring diagrams and am overwhelmed to say the least. From what I can tell, there should be power at each panel (panel being the black connector that the switch plugs into) at terminal number 328 (for passenger front and both rear) and terminal number 400 “a” and “b” (for front master panel). Is this correct?
I also assume that the bypass switch has to in proper working order for this whole system to work, as from what I can tell, each switch is wired through each other starting with the bypass switch. I also notice that stamped metal plates go between two pieces of “paper” on each master switch assembly. I assume these are also necessary.
Here’s the question I have – is there a terminal (or multiple terminals) I can test for power (12V) to rule out faulty wiring and prove an inoperative switch, and how do I test a window switch to make sure it works, or is there a better Troubleshooting procedure for my current issue?
Thanks in advance for consult!
Hi Dan –
We are glad that the Lincoln Land blog was able to help you. Some of the problem areas can be complicated at times and the power window circuits can be one of these areas. The power to operate the motors must travel from the switch to the motor and then to ground from the motor through the same switch. For the out board windows (rt. frt. and both rear 1/4 windows the power must travel not only from and back to the drivers switch but also in and out of each remote sw. as well. There is no easy way to address some of these issues and accurate diagnosis is very important. The only way to correctly diagnose the system is to test the power path of the circuits with the use of a 12v test light and the wiring diagram. The switches themselves have proven to be a big problem and many owners just go ahead and remove all of their switches and have them serviced but being able to diagnose only the faulty ones can be a real dollar saver. All of the wiring etc. of course must be intact with good connections to the switches as you indicate yours is or was. In addition to all of the above the rear side windows can suffer with some of their own special problems such as binding from lack of use and gear issues. If necessary please contact us further and Al may be able to offer more advice.

Have a Question? Submit your question to Bill!

Submit your Question

Your Selected Vehicle