Climate Control saga continues!

[scottmo@tekig5.pen.tek.com (Scott John Mockry)]

My climate control system (86 5000CS Turbo) acted up again this weekend
so I opened the glove box and looked at the position of the servo arm on
the main controller. The arm should be pointed to the left when the system
is set to 60 degrees.  When it malfunctioned the arm was in the middle
of its travel and when I gave it a gentle nudge it moved all the way to
the left where it is supposed to be. The servo arm moves the cable that
controls the blending flap that directs air through the heater core. 
I removed the cable from the controller but did not find it binding
at all. In fact there is a spring that tends to pull it left towards
the cold air position. I removed the controller and checked the
connections but found no corrosion. The servo motor has a potentiometer
connected to the shaft to verify what position it is in. I sprayed some
contact cleaner into the potentiometer and ran the servo arm back
and forth by raising the temperature up and down. It was 
working fine so I reinstalled the controller. Of course the system 
malfunctioned again on the way to work today. I am going to check the
output voltage of the potentiometer when it is working correctly and then
check it again when it malfunctions. The search continues!!!!!

I also found the source of the exhaust leak that I've been hearing in the
morning, exhaust manifold stud for #1 cylinder is broken off. The service
bulletins state that this was a problem until 1987 when they installed
improved exhaust studs. This looks like a fun project! It may be easier
to remove the head with the intake and exhaust manifolds attached than
to try and pull off just the exhaust manifold. Has anyone tried pulling
off the exhaust manifold on a 1986 5000CS Turbo?
Scott