If your ECC is working properly, with the thermostat set at 90*, the arm on the actuator should be all the way RIGHT (right being the passenger side of the car) and at 60* it should move to the extreme left position. Assuming you're getting air blowing out the vents (i.e. the fan is blowing), pull your glove box out and, using a flashlight, look through the peep hole in the black dash brace and watch the actuator arm. There'* an article on www.trialsnuts.com/ecc.pdf that has some pictures at the end of it that will help you find what you're looking for.

Repeatedly set the heat at max and min and watch the motion of the arm. It should move smoothly and move to the extents of travel consistently. Any irregularities point to a hosed air mix actuator.

Stan, can it also happen that the link on the motor comes undone so that the arm moves but not the flap? Can that be seen through the little hole too?

Yes, it can be seen through the peep hole, and that is certainly possible, but improbable. The rod is metal and is actually threaded on the end that snaps into the arm. While it looks like the rod threads into the arm, it really does just snap in. There'* enough friction there that it would be very unlikely that it would slip at that juncture before failing somewhere else. Having said that, you've made a good point, Bill, and it would be prudent to watch the connection at the arm/rod to make sure there'* no slippage. History indicates this would be a highly unusual failure mode, however.

Agreed. I like the thoughts here about the rod possibly coming unhooked, and it'* in there pretty darn tight. Unlikely, and worthwhile looking at while observing the actuator moviement.