[s-cars] Ready, Shoot!, Aim (heater flap issue - sunday garage mayday!)

[Steve Voit]

Hi S-heads:

I'm uncharacteristically unprepared for what I'm doing.  Can't get defrost
and have coolant leak, so I pulled the heater box and am reworking with new
core and flap servo.

 

Rather than look at codes (d'uh) I just ordered the foot/defrost servo
because it said 'defrost'.   Come to learn that a defrost problem can also
be the central flap servo - as this directs air to upper vents or to the
choice made by the downstream defrost/floor servo.

 

I'm feeling stoopid now, because it's all disassembled and I don't know
whether the servo I bought is the problem one!  Is there concensus regarding
which servo of the two is usually the problem?  I'm thinking I might want to
replace both as long as I'm in there, but OTOH if one of the two is usually
the culprit, then I'll just go with it.  With everything disassembled I
don't expect useful information from the climate control codes.

Advice? 

95.5 S6

Steve V  Seattle