INDICATOR 8T5250 - Caterpillar

Illustration 1. 115-0627 Air Conditioner Group and 115-0628 Heater Group
(13) Harness Assembly. (14) Actuator. (15) Water Valve Assembly. (16) Electronic Control Module. (17) Blend Door. (18) Motor Assembly. View D-D represents the pin assignments for the harness assembly (13). If voltages are wrong at actuator (14), recheck motor drive (17) and potentiometer positive (+) and negative (-) with actuator (14) unplugged. If voltages are correct with actuator (14) unplugged, replace actuator (14). If not, verify harness (13) is correct before replacing the electronic control module (15).If voltages are wrong at a potentiometer, unplug and verify that the resistance between the (+) and (-) leads is approximately 5000 ohms for the control potentiometer and 10,000 ohms for the actuator feedback potentiometer. If the resistance is too low or shorted out, the controller will operate incorrectly.
When the control powers up, it calibrates itself by moving blend door (16) to each end of travel. The calibration takes 20 to 30 seconds.