Part 2 of 2

Flowchart C-12B (2 Of 2):

Chart C-12B Circuit Diagnosis:

TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.

1. There should be 12 volts available to circuit 339 and circuit 2 on each relay when the ignition is "ON".
2. This test checks the ability of the ECM to ground circuit 335 (circuit 473). The "Service Engine Soon" light should also be flashing at this point. If it isn't flashing refer to Computers and Controls / System Diagnosis / Diagnostic Charts / Chart A4-2. Chart A4-2 No Code 12 Service Engine Soon Light on Steady
3. If the fan does not turn "ON" at this point, circuit 702 (535) or circuit 150 is open, or the cooling fan motor(s) are faulty.