Power Window Dead - C3

[Rob H.]

Hey there - My driver's side power window of my '69 L36 just died. I am assuming that the motor finally gave out since it has been getting progressively slower and slower. When I push the button down there is nothing (the passenger side works like a charm).

My question is whether I should try to rebuild the motor or simply replace it? I see that Dr. Rebuild sells Delco replacement motors for $210, as well as the individual parts.

I would love to hear from anyone who has been in a similar predicament and which way they went, and/or if they have any advice on the replacement/rebuild procedure.

Thanks in advance!

Best,
Rob

[Pat M.]

Re: Power Window Dead - C3

I bought a replacement from O'Reilly's for my 70's driver's side window. It looked almost identical to the original, works perfectly and passed PV, and was about $150 with the core credit.

[Frank P.]

Re: Power Window Dead - C3

Be sure to check out the power switch before purchasing a motor. I bought a new motor for my 1977 and found that the switch was faulty.

[Richard C.]

Re: Power Window Dead - C3

rob dont forget to LUBE all the tracks and regulator dont forget the pivit points and spring

[Rob H.]

Re: Power Window Dead - C3

Frank - I considered that the switch might be the culprit, but since the rate at which the window went up keep getting slower I figured it had to be the motor?

Richard - I read a past thread about the importance of re-lubing the mechanism. Any grease you would recommend over another?

Pat - Thanks for the heads-up on O'Reilly's!

Thanks for your feedback!

Rob

[Terry M.]

Re: Power Window Dead - C3

Frank - I considered that the switch might be the culprit, but since the rate at which the window went up keep getting slower I figured it had to be the motor?

Richard - I read a past thread about the importance of re-lubing the mechanism. Any grease you would recommend over another?

Pat - Thanks for the heads-up on O'Reilly's!

Thanks for your feedback!

Rob

Don't rule out the switch just because the failure mode was gradual. A poor contact in the switch, eventually burning the contacts open, will result in the kind of failure you experienced.

The power window switch circuit on Corvettes, with only one switch per side, is really simple. A multimeter and wiring diagram are all you need to properly diagnose the situation.

[Rob H.]

Re: Power Window Dead - C3

Don't rule out the switch just because the failure mode was gradual. A poor contact in the switch, eventually burning the contacts open, will result in the kind of failure you experienced.

The power window switch circuit on Corvettes, with only one switch per side, is really simple. A multimeter and wiring diagram are all you need to properly diagnose the situation.

Terry - I don't have a lot of electronic experience...what would be the procedure in layman's terms?

Thanks!!!
Rob

[Steven B.]

Re: Power Window Dead - C3

Rob, I had the exact same problem. It was the switch. If you don't have a meter a quick way to test, if the other switch is OK, is to just swap switches and see how it works.

Good Luck!

Steve

Also, if you don't have a meter and/or don't know how to use one you can get them for not much $$ (about $20 and up) and they have directions included. They are really very simple to use.

[Terry M.]

Re: Power Window Dead - C3

I'm kind of guessing here, because I have never seen the backside of these switches, so keep that in mind.

I expect there are three contacts on the back of the switch. You will have to access the backside of the switch with the wires still hooked up. You are on your own as to how to do that, because my Corvette doesn't have PW. If you have to remove the parking brake console, like I think, you better ask about that. That one has a trick to it. Having the AIM is almost essential for a first-time parking brake console removal.

There should be a switch position on the meter for DC volts. With the meter switch in the DC volts position put the black lead on a good ground (some metal part of the car) touch the red lead to the center wire of the driver's side switch. If you are careful a paperclip can usually be used to probe the center connection from the underside. Do this with the wires hooked up and the ignition switch on. The meter should read 12 to 14 volts, depending on the state of the battery charge.

Put the red lead on one of the other wires and move the switch to either the up or down position. The meter should read the same voltage as it did before if the switch is good.

Do the same for the last wire.

If the switch is good you will get the same voltage reading on each of the wires as the switch is actuated. Any lower voltage readings (voltage drop) indicate the switch is making poor contact and should be replaced.

If Jack Humphry sees this (I haven't seen him on here in a while) he will be able to tell me how wrong I am. There are probably a few others who could do the same, so don't dash right out to the garage. As I said, this is off the top of my head without ever having to do it to a Corvette, and not having the wiring diagram in front of me.

You should try it on a 4-door car with two switches for three of the four doors. I've been there and got that t-shirt -- and it is no fun.

Good luck

[Rob H.]

Re: Power Window Dead - C3

Thanks for the run-down Terry! I surely hope it is just the switch like Steven.

Really appreciate the info!

Best,
Rob

[Frank P.]

Re: Power Window Dead - C3

The easyest way to test the switch is with an ohm meter. One of the poles will be common, one for up and one for down. With the meter leads connected to the common, and each leg, you should see continuity when you press the switch. They do wear out and the contact area becomes ineffective.

[Terry M.]

Re: Power Window Dead - C3

Frank,
I thought about telling Rob to do it that way, but if the contacts are worn (high resistance) the ohmmeter may not put enough load on them to show they are bad. I thought the load of the motor would be a better check.

[Frank P.]

Re: Power Window Dead - C3

Terry:

That is true. That is why I always use the highest range on the ohm meter. I figure that if the contacts are worn so bad that they give a problem reading I will replace the switch first, then proceed.

[Robert R.]

Re: Power Window Dead - C3

Rob,
Have you looked inside your door as to the condition of your tracks, lubed or not?
Also did the slowing down occur as the weather got cooler?
An experience I had was similar to what you described. After cleaning off the old lube my windows worked very nicely with out changing either the motor or the switch.
Just a thought.
Bob

[Richard C.]

Re: Power Window Dead - C3

rob, dont forget to CLEAN OUT ALL OF
the OLD GREASE in the tracks. you will find it is hard and dry. i use syn wheel bearing grease. also be carefull!!!!!! there is a verry bad spring in there call me at the shop @ 615-255-3939 i can help better on the phone