Power Window Operation theory.

I'm wanting to operate the windows with the truck off, dead to the world, not in accessory mode. I have studied the "Power Windows with Jam" schematics to familiarize myself with their operation and why they only operate when the ignition is on. 12VDC power to the window switch controls seems to be present "at all times" direct from the battery, but there are other connections of LIN, LIN1 and LIN2 from the Body Control Module to the Front Door Window Switches. This would seem to "activate" the window switches. Does anybody have the write up as to how the circuit functions?

 

Calling @caribe makaira

 

What, do not understand.

 

I bet, without having looked at or ever been in a 3rd gen, the BCM is what controls the window motors; the switches just 'request' the window go up or down. I suspect you're gonna have to trick the BCM somehow into thinking the truck is powered up, which is gonna have side effects.

 

Switch them out for crankolator winders

 

Could just bypass 12V -> motor? Throw some diodes in there

 

If the switches can handle the current, but you might lose safety features and the one tap up/down. I suspect it’s all through the bcm so it can watch the motor current for stalls and remember where top and bottom is.

 

Well ya but does OP really need all the "safety" features if they just want to roll the window down with the truck off?

IMO digging into modifying the BCM for something that can be accomplished by a dual pole switch between the battery and a load is a fool's errand, but I have no 3rd gen experience

 

Yeah thats fair. I wasn't considering replacing the switches entirely. God help us if its some sort of PWM servo signal to run the motors

 

Or if the BCM tracks positioning of the windows or something.. so it wont roll back up all the way if you turn off the truck then move it while off.... but then you just have to make sure you note where it was when you turned it off

..whatever, this is why I own a 1st gen.

 

The BCM indeed controls the door window switches by enabling their operation, that is where the LIN leads shown in the schematics come into play. All power to the window motors is controlled locally at each of the front doors so the large current is controlled/directed by relays within the window switches, so no window moving power comes from the BCM, just a control voltage or ground I don't know yet which it is.

I have found that looking only at schematics often does not give the complete story of a circuit's operation that is why I'm looking for a "theory of operation" so I do not have some unexpected "side effects" as you say.

 

Sounds like we're spitballing the wrong way then. I don't have schematics for the 3rd gen though, not much to be done without them.