B3787
B3787 - Blower Motor Relay Control Circuit LowSchematic:
CIRCUIT DESCRIPTION
The BCM provides ground to enable the after blow operation through circuit 247 (retailer installed accessory) and the relay located in the IPFB. Circuit 247 along with the after blow relay are retailer installed. The BCM provides the logic to enable the blower based on information from the engine control module (ECM). The duration of the after blow is determined by A/C operation, ambient air temperature and vehicle speed. This DTC will fail when circuit 247 is shorted to ground for 5 seconds when the output is Off.
DTC PARAMETERS
^ Output = Off
^ Short to ground 5 seconds in circuit 247
^ No light will illuminate in I/P
DIAGNOSTIC AIDS
^ Check for poor connection at BCM. Inspect harness connector for backed out terminals, improper terminal mating, broken connector locks, improperly formed or damaged terminals and poor terminal to wire connection (terminal crimped over wire insulation and not conductors).
^ Inspect wiring harness for damage. Check for broken or chafed insulation.
^ Check for poor connection at the low coolant switch.
^ If fault is suspected to be intermittent, wiggling harness wiring may help in locating fault.
TEST
Diagnostic Chart:
