Hi all,I've recently bought an '88 505 GTD with plans to use it as a daily. There's a few little bits and pieces that I'd like to get sorted before I do so; namely getting the heater to work.The fan, and air directional buttons all work OK, but no matter what the temperature slider is set on the air output is still stone cold. I've done a bit of reading up on the issue and from what I can gather it's likely to be either dodgy contacts inside the temperature slider, or a stuck heater tap.I managed to fire a fair amount of contact cleaner into the front of the temp slider and from what I can see everything in there looks nice and clean. This leads me to believe that the tap might be the issue? From what I've read it lives on the inside of one of the wheel wells, but I for the life of me can't find it.Does anyone have any suggestions from where to go from here?