Chart 3 Improper Blower Speed

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The programmer sends a variable voltage signal to the power module which is then amplified and sent to the blower motor. The programmer monitors the blower feedback voltage so that the signal can be adjusted to achieve the desired blower motor speed.

TEST DESCRIPTION

Numbers below refer to circled numbers on the diagnostic chart.

1. This step categorizes the problem: short to voltage on blower control or feedback circuit, open feedback signal or inaccurate/improper sensor input.

2. This step checks for a short to voltage on CKT 754.


3. This step checks for a short to voltage on CKT 65.


4. This step checks for an open or short to ground in CKT 65.


5. This indicates an inaccurate sensor reading causing the ACP to command an improper mode. Typically a bad sensor input would also affect temperature control, so you are referred to Chart 5 for sensor checks.