The resistor I'd selected was something available from radio-shack that would have similar characteristics to the lamp you'd selected. I was thinking you wired the lamp up in parallel to the PTC. If instead you bypassed it, I've mis-understood your fix. I was thinking the PTC would still pass the current for most uses if the mechanism and the seals were refurbished and working well. Isn't it true that the resistor (of whatever type) would then dissipate some of the energy while allowing some power to flow to the motor.
I was not thinking the PTC would be so degraded that it wouldn't even be able to handle the initial inrush current. If that's true then that would explain why my windows won't open even when the mechanism is getting manual assistance.
So should I just get new actuators and upgrade them with this fix before installing?
By the way, the root cause of the issue is not the PTC. The root cause of the issue is high load on the actuator motor. This is most likely from dirty, old, and/or frozen window seals.
The posted procedure is very well documented and I love the detail you gave. I'm an engineer and have encountered a similar issue on the Ford Expedition 3rd Row Power seats. I'm going to try this type of "fix" on that issue to help that PTC cool faster.
May I suggest you add something to your posted procedure for this though? Just a quick note at the beginning something to the effect of:
"Before opening your trim panels, try applying silicone grease to as much of the window seal as you can and clean the mating surface of the glass. Re-test to see if the windows now function more normally. Do not hold the buttons down for more than 5 seconds if the window doesn't open."
Instead getting and wiring two bulbs you could get the following. A two pack wire-wound resistor at radioshack for $2.50. That would be enough to fix both windows.
The only issue I have with the posted solution is the un-likely event of the switch being continuously actuated for a long period of time. The bulb will dissipate the energy in light and heat, but since the procedure asks to shrink wrap it the light energy gets absorbed by the shrink-wrap and turned into heat (and degrades the shrink-wrap). This could cause a fire. If high quality shrink wrap is used, the bulb may burn out quickly and the original condition would present itself again. (during normal usage this would never be a problem)
A resistor would be easier to wire without all the shrink-wrap and therefore less chance of a fire as resistors are designed to dissipate energy at their rated capacity.
Instead of a small bulb you could use one or more resistors to give you 50 Ohm resistance with a minimum 5 watt rating at 14 Volts.
It would work the same way as the posted solution because the "fix" works by bleeding off some of the power that otherwise goes into heating the PTC in a motor stall condition. It would be easier to solder a resistor compared to a bulb and probably cheaper too.
The only bad part of using a resistor would be you wouldn't have a visual check to see if you wired it correctly. You would have to feel if it got hot when power is applied with the motor stalled.