I did the following tests on the climate control system using the 10 prong plug and following the test procedure that was sent to me:

pin 4 and 5 - in car sensor - within spec
pin 2 and 3 - ambient sensor - within spec
pin 9 and 10 - tempurature dial - within spec

For amplifier testing section
Set to cold - pin 1 - no volt reading
Set to cold - pin 6 - no volt reading
Set to heat - pin 1 - no volt reading
Set to heat - pin 6 - no volt reading

I did test touch the tester to a know hot source to indicate that I was reading 12 volts. I had to make sure I had good ground.

According to the instructions this would indicate that I had a problem with the amplifier and not the servo.

Was this test sufficient to justify paying $120 for a new amp?