Possible Causes

An open in circuit 1381 (WH/LB), 1375 (PK/YE), 1376 (BK/LB) or 1126 (LB).
A short to ground circuit 1381 (WH/LB), 1375 (PK/YE), 1376 (BK/LB) or 1126 (LB).
A short to voltage circuit 1381 (WH/LB), 1375 (PK/YE), 1376 (BK/LB) or 1126 (LB).
A short together circuits 1375 (PK/YE) and 1376 (BK/LB) or 1126 (LB) and 1381 (WH/LB).
Auxiliary temperature blend door actuator.
SJB.