Ryan Fairchild

So here we go with another power window issue!
I have a few ideas as to what the issue is, but before I go tearing into wiring I'd like to get some input.
My front passenger window will roll down from both switches, but refuses to roll back up. I took off the door panel and disconnected the motor terminals, and when I roll the window down the switch provides 12 Volts to the motor, but when I roll it up it only provides 8 tops, clearly not enough to put the window up. I have opened up the switches on the driver and passenger door, and don't see any cracked solder connections. Any ideas as to what to attack first? And if you say to look at the wires in the boot, what colors are the wired going to the switch? Thanks!