1971 Mark III Slow Windows & Update….

Hey Bill,
I am a die hard Ford/Lincoln fan! Currently my 71 Lincoln Mark III has been having an issue with slow windows. I removed the regulators and replaced the motors and greased the guides with white lithium grease, installed new belt line weatherstrip. I put everything back together and they go down fast but go up slow. The drivers side is better, still slow but does not stop, the passenger is still real slow and I have to pull up to get it to raise. I know these windows are big and heavy but I am at a loss. Not sure if an old really would be the cause.
Thank you
Alec
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Hi Alec –
I think that you should first determine if your issue is with the electrical circuit to the motors or mechanical. If the regulators and their springs are correct and assembled correctly and the motors are within specs. the springs will counterbalance the UP and DOWN action to be equal and of a reasonable speed as designed. To find out if you have an electrical problem you should remove the trim panels and operate the motors from their connectors near the motor by temporarily jumping them direct to the battery. If they operate correctly up and down with this test then you will need to correct the electrical power path through the switches and all of the associated wiring. Be sure that your battery is fully charged and use a battery charger on the battery when performing these tests. If you find however that the windows are still slow during the above diagnosing then you will need to revisit the motors and regulators etc. inside the doors. If you have purchased your window motors or other repair parts from Lincoln Land and have determined that they may possibly be faulty, please call and ask for Al for further assistance.
Sincerely,
Bill
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Bill,
Thank you for the help I used a portable jump starter to power the windows and they went up extremely fast. However when reconnected to the vehicle wiring the window again moved slow. I then checked the wiring to the motor and when the switch is activated I get 12.5 volts to the motor. I did verify a good ground under the hood as well. Is it possible the safety relay could be preventing a constant 12 volts under load?
Thanks again for the expert advice I really appreciate it!
Alec
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Alec –
Yes, as you are suggesting it is possible that the power window relay has a less than perfect connection inside and this can be proven by jumping the wiring at the relay. The direct power supply to the relay of course must also be in excellent condition. Our experience is that if there is a power drop at the p/w motors it is usually caused by the Sum of Several bad contacts in the circuit and that switches usually need replacing or servicing. You should use the proper diagrams to study the power path to and from the individual p/w motors and become familiar with the many contacts of the circuit inside the switches and the location of the grounds. You will then see that there are many locations for poor connections to develop. To do these tests and any other circuit testing you are well advised to have the correct wiring diagrams. From the diagrams you will learn that the circuit path is lengthy as power to each window motor originates at the drivers door switch and then returns back from the motor to separately ground in the drivers door.
Sincerely,
Bill