It's a long story. Quite frankly, I'm just frustrated with the whole thing. You commented on it - reference this post: http://www.picbasic.co.uk/forum/showthread.php?t=17476

What it boils down to is my laziness to add a few extra components (mostly limited by PCB space) and spend $1 more. I won't rehash the thread above but this is where I'm at now.

My original solution of using the capacitor with PWM is what I'm back to testing for the final solution. The only reason why I wasn't able to use it in the first place was due to the fact that I'm cheap and didn't want to use an analog input to know the true temperature. I maxed out the frequency but I still needed a fairly large capacitor to smooth out the PWM signal. With the larger cap, the voltage takes too long to drain down and taking temperature measurements with the OEM computer isn't viable.

However, I realized I could simply use the dutycycle to know approximately where I was at with regards to the actual temperature. The temp can be + or - 2 degrees so using approximate values for the duty cycle is not a problem.

My reasoning for using a relay (reed relay perhaps) is due to a voltage divider. I was going to use a voltage divider that was connected to +5 and -5 100% of the time. I would use the relay to supply the voltage to the thermistor input. Since I wouldn't need a capacitor, I could instantly capture a measurement. The other solution is to just buy a voltage regulator with two outputs where at least one has an enable input and adjustable output.

So for now, the PWM output and using the duty cycle to approximate the temp is working.