Im currently in the process of replacing my drivers side window motor and regulator. Ive got the new regulator into the track and am in the process of bolting the part in place, problem is that the guides ive been using say i'll have to raise and lower the regulator to get the holes lined up, but after I raised the window up to far it would not go back down.
I've used a tester to be certain that power was making it both ways to the motor and it is and also switching polarities when the switch changes direction. I've checked the schematics and see there is a power window module somewhere, not sure if that may be the problem.
I know its not the motor itself because Im replacing the passenger motor next and hooked that one to the connector and it did the same thing (responded on up, but does nothing on down).
Has anyone else had a similar issue or know if it is that module? I tried searching and couldnt find this scenrio.
Gen 4 Firebird

 

Welcome to the site!

There are a few things you should be aware of before you go further.

The preferred method for motor replacement is the shbox method. (You can search for the shbox site and see how he came up with the alternate replacement procedure.) The door panels are very fragile and don't handle having the regulator rivets drilled out well... The shbox method avoids this step entirely, but it looks like you are past the point for that being an option.

When you reinstall the regulator, you MUST use the special GM rivets to re-attach the regulator to the door. (not bolts or regular rivets) The GM parts are a special aluminum jacket, steel mandrel rivet which is suited to the composite material the door is made out of. (This will probably require that you purchase a special oversize pop riveter capable of handling 1/4" rivets. If you shop and get one online, I recall they can be had for $35.) The rivets can be had from any local GM dealer. People not heeding this caution will develop this serious issue: https://ls1tech.com/forums/general-m...or-rivets.html


So, you've tested the power at the motor connector? If so, then you are fine. The window module is not an issue.


Don't be so sure it's not the motors. This motor was first used on GM cars in the '60s and the market is flooded with (very) bad remans. It's not uncommon for multiple motors, "new" from the store, being bad out of the box. I recall we are close to over a decade since this motor was made by GM, so typically all you can get (even when the motors are labeled "new") is a reman motor.

There are some companies that have made truely new motors, but it's uncertain if they can still be had at the moment.


Another common issue is the motor connector. It's very hard to get on to the motor properly - particularly when it's in the door. You'll need to make sure your door speaker is out and you may need some mirrors to check it out. The connector can go "on" without making electrical contact.


Where did you buy your motor/regulator assemblies? What part numbers are they?


You may also try putting 12V to the motors off of the car and see what happens. Also look and see if there are safety locks on the regulator keeping them stationary. (The regulator, without the motor, has a very powerful spring that can take a hand off.)

 

Thanks for the info. The only thing yhat makes me suspicious is that the motor will go up just not back down, even when I hook in another motor. I may try using a 12 volt to test the motors out side of the window.

Also the motor and or regulator had been replaced once, before I bought the car, I removed bolts instead of rivets and there were alreasdyvsome bad holes drilled. Im not too upset about it, Im planning on getting new doors later down the line just trying the get this working for the time being. Hope fully the passenger side hadnt been gutted like the drivers side.

 

This is an odd issue - The OP is stating he used two different motors on the same door and both have the same issue - they wont go down...

So I have a few questions as well..

When going up, does it roll up normally? ANY abnormal resistance at all?

Also... It sounds like you replaced the entire window regulator / motor assembly, meaning the motor is still intact with the regulator which makes troubleshooting difficult. The motor can actually be removed from the regulator BUT DO NOT DO IT WHILE THE REGULATOR IS NOT SECURED (and I mean ALL rivets in place) TO THE DOOR, THE HALF MOON GEAR CAN LITERALLY RIP OFF YOUR HAND!

Did you try ONLY the motor, NO REGULATOR ATTACHED TO THE MOTOR - with the Drivers Side door connector? The reason I ask is I want to see without ANY resistance on the motor WHATSOEVER, not even the regulator, if the motor will spin when you try to roll it down... If it spins, then the regulator is either improperly installed, or something is wrong with it or one of your roller guides because whats happening is it reaches a point of resistance and triggers a circuit breaker causing the motor to think that its already in the down position thus, stopping the motor before it even starts.. ..If it DOESN'T spin.. ..well...things only get more complicated from there...