Should I just replace it, or is there something I should be looking for?

 

I'd replace it, but only if you can get one out of the JY in case it's not the problem. Don't go buying one at the dealer.

And that switch the top one is all vacuum controlled. So check ALL the vacuum hoses under the hood and under the dash the best you can also.

 

I have the a/c condenser unplugged and my heat has dissipated again, back to luke warm air
Any ideas?

 

I will check out a jy and see if I can get one.

 

Any luck tracking this problem down? I literally am having the same exact issue, the only difference is that I went ahead and put a new thermostat in mine. The aftermarket one that the previous owner put in was, for whatever reason, not allowing the truck to get to operational temperature. It now operates within normal parameters, but I still have no heat. Under the dash the heat source is all the way hot, but coming out of the vents is not. Winter is coming and I live in the mountains. This is quickly becoming an issue.