MacGuyver > Modern car electronics

[MinisterofDOOM]

It's pretty common, especially around here, where there are a lot of us who are fond of 20+ year old cars, to hear people talking about how much simpler older cars were to work on. Fewer electronic modules, simpler mechanical implementations, fewer things to go wrong, etc. I agree to a point. But modern car tech isn't completely immune to tinkering and driveway ingenuity.

I used a 69 cent spring to force a solenoid closed on my Lincoln's dual-zone climate control coolant control valve. It's got one inlet and two outlets regulated by two solenoid-operated valves (one for each zone). My passenger side has only been blowing crazy-max-hot, and I decided the control valve had to be the culprit. So I took the thing apart and crammed a spring in one of the solenoids, forcing the plunger down and the valve closed. The result is NO heat at all, but as it's only the one side and summer is (supposedly) around the corner, that's not a problem. $0.69 is a lot better than $150 for a new control valve.

Even better, though, it appears my disassembly and inspection of the solenoid assemblies might have actually solved the problem (the spring is obviously a workaround, not a solution). I discovered, once I had a chance to warm the car up and test the HVAC output, that I got the wrong valve...I actually jimmied the driver side, which is indeed stuck on cold. The cramped enginebay and centralized dual heater core setup made it hard to tell which valve went to which core. (Z32 guys would feel a lot better about their situation after seeing my enginebay).
BUT...the passenger side no longer appears to be stuck on max heat. It now seems to vary heat output appropriately, depending on the automatic temp setting. I'm guessing the solenoid for that side must have just gotten stuck. So hopefully if I just remove the spring from the driver side valve, I'll have properly working climate control again. And if not, at the very least I can just swap the spring over to the other valve and still keep proper operation on the driver side.

Cliff notes:
Expensive climate control component on my Lincoln is bad, passenger side only blows hot.
Bought a .69c spring and jammed it in a malfunctioning control solenoid to cause it to fail closed rather than open.
Modern car tech pwnd by driveway ingenuity.

[PoorManQ45]

Indeed. you can still fix things on the cheap in some instances. Good job