BCM Code B337: Loss Of A/C Heater Programmer Data: Notes

If BCM has lost data communication with A/C heater programmer and ignition is on, Code B337 will set. Fault can be caused by a loss of 12-volt power, ground to programmer or a double open in programmer data line, one on each side of component. During a failure, A/C clutch is disabled and blower motor runs at a constant 6 volts.

Test Number 1)  Ensures code is not intermittent.

Test Number 2)  Determines if fault is due to power or ground circuits or data line.

Test Number 3)  Determines if data line fault is due to wiring or programmer.

Test Number 4)  Checks for IGN 3 to programmer.

Test Number 5)  Determines if loss of ground is due to programmer, wiring or CPS.