Hi. I was hoping to get some insight on an issue with my climate control. I just got an 87 300TD that only blows hot air out of the vents. I checked the mono valve and of course it is not closing. It has 12v on one pin, however, the other pin is never grounded, even when the climate control is set at its lowest setting. I jumped the ground pin of the mono valve to a ground, and the valve vibrates a little bit, but doesn't shut off coolant flow. I am guessing that the mono valve is shot. I will check the current draw of the valve when I have my multimeter handy. My questions are...

Can I fix the mono valve with one of those kits?
If the coil of the valve shorted, would it take out the climate control unit?
Is this a common problem that can be fixed by changing a component/ or fixing a burnt trace?

I have decent mechanical and soldering skills, so if these things are fixable, I would like to give it a shot. I like to not have to buy a $300 CCU.

Thank you for the advice.