For years I've had an expensive gowesty heater valve in my 1983 turbo
diesel Vanagon westy. This summer, with actual temps breaking 100 commonly,
the heater started blowing hot air and adding 10+ degrees to my cabin
temperature. Today I took a look at that and made these improvements that
fixed the problem:

Pulled the instrument cluster and the control lever assembly from the dash.

Found that the wire cable that controls the heater valve had kinked the
last time it was turned off of heat. This left the heater valve open even
when the heat lever was turned all the way down--the hot water valve was
not getting the message.

I used a gadget that I have gotten so much use out of over the years on my
vanagon for any wire that runs through a cable sheath--a motorcycle cable
lubricator--to shoot chain lube from a spray can all the way down the cable
sheath.

I rerouted the cable underneath the dash so it took the most gentle path
possible to the lever.

I loosened the cable clamp on the lever assembly and moved the clamp point
so that it cut off earlier rather than later as the lever was moved to the
left hand "off" position. I gently reclamped the cable using the least
pressure possible so as not to bind the wire as it passed through the cable
sheath.

I straightened the wire as well as I possibly could with a pair of longnose
pliers.

I used said pliers to push and pull the wire through its entire range of
motion. excercising it in and out of the sheath until the cable lube was
definitely doing its job.

I used said longnose to bend the cable anchor tab (the rectangular sheet
metal tab of the lever where the wire inserts into it) in a twisted fashion
so that the left hand edge was about 15 degrees higher than the right hand
edge. This angle helped the wire, with its double-90-degree crook in it,
fit more securely and got rid of a lot of the vertical slop that allowed
the kink in the wire in the first place.

Success! Didn't even have to get under the van.

Jim