How do you make a power window drop (half inch or so) on opening door?

[VRaptor SpeedWorks, LLC]

Shane,
I'd be surprised if no one would like this function, especially with the frameless windows, and the variation of seals I am seeing guys using. Especially if using a captive seal.
I think that I am going to incorporate something to make this happen, I think it will help my (self-imposed I admit) door seals.
I think it can be as simple as a timed relay firing the window motor for 1/2 sec or so when the door begins to pop open.

Here is a timed relay that has a minimum duration of .2 seconds for $20
https://www.amazon.com/Timer-Delay-R...imed+relay+12v

Here is an adjustable relay 0-20 sec for $8
https://www.amazon.com/GERI%C2%AE-Re...imer+relay+12v

So for you electrical gurus, would one relay work for both the up and down functions of the window motor, or would you need one relay for each direction of window travel?
Thanks

That's why this gets so complicated. I don't think either of the relays you linked to would work as the one is only rated for 5A and the other looks to be good for 10A. The 10A relay might last a little while, but you're using up every bit of that 10A. Also, you don't just need one relay for up and one relay for down. You have to flip the polarity of the motor....so you would likely need 4 relays per window......one that controls + up....one for - up.....one for + down and one for - down....and they would all have to be wired to work when you need them to work, but not interfere with normal window operation from the window switches or the other set of relays.....for instance, it you're not thinking and you are manually rolling the window up with the window switch while you open your door.....the switch is giving the motor power and ground to go up, and the relays would be applying power and ground for the window to go down which would instantly result in either blown fuses, destroyed timer relays, burnt window switches or all 3. As I said in my first post.....complicated.

[beeman]

That's why this gets so complicated. I don't think either of the relays you linked to would work as the one is only rated for 5A and the other looks to be good for 10A. The 10A relay might last a little while, but you're using up every bit of that 10A. Also, you don't just need one relay for up and one relay for down. You have to flip the polarity of the motor....so you would likely need 4 relays per window......one that controls + up....one for - up.....one for + down and one for - down....and they would all have to be wired to work when you need them to work, but not interfere with normal window operation from the window switches or the other set of relays.....for instance, it you're not thinking and you are manually rolling the window up with the window switch while you open your door.....the switch is giving the motor power and ground to go up, and the relays would be applying power and ground for the window to go down which would instantly result in either blown fuses, destroyed timer relays, burnt window switches or all 3. As I said in my first post.....complicated.

I would definitely feed the voltage from the timed relays through a high amp Bosch relay. If you pair up a couple of Bosch relays, you can make a system that flips the polarity to the window motor depending on whether you want the window to go up or down. So I agree, you would need 2 Bosch relays and 2 timed relays per window, or just make both windows move in tandem. I'll attach a schematic I found, timed relay could provide pos or neg pulse.

429_actuator.gif

actuator_control_neg.gif

As far as an electronic limit mechanism, are they common on car windows? I know that physical limits exist. Seems that even on late model cars I've owned, if the window is all the way up and you hit the up switch (like checking your windows are all up heading into the car wash), you still hear the window motor trying to push the window up farther.