Cavalier/Z24 V6-173 2.8L (1989)
Chart C-12 Wiring Diagram
TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.
1.
12 volts should be available to both terminal "E" & "C", when the ignition is "ON".
2.
This test checks the ability of the ECM to ground CKT 335. The "SERVICE ENGINE SOON" light should also be flashing, at this point. If it isn't
flashing, see CHART A-2.
3.
If the fan does not come "ON", at this point, CKT 702 or CKT 150 is open, or the cooling fan motor is faulty.
System Diagnosis
Coolant Fan Does Not Run
1.
Turn ignition switch to RUN position and connect fused jumper between ALDL connector white/black wire terminal and ground. If coolant fan
runs, problem is ECM related.
2.
If coolant fan does not run, turn ignition switch to RUN position. Disconnect ECM connector and connect fused jumper between C1 (VIN G) or
C3 (VIN T) and ground. If coolant fan runs, problem is ECM related.
3.
If coolant fan does not run, leave fused jumper connected as in step 2, disconnect coolant fan relay connector, turn ignition switch to RUN position
and connect test lamp between terminals as follows:
a. Connect between terminal 5 (brown) and ground. If lamp does not illuminate, check fuse and brown wire for open.
b. Connect between terminals 5 (brown) and 2 (dark green/white). If lamp does not illuminate, check dark green/white wire for open.
c. Connect between terminal 1 (red) and ground. If lamp does not illuminate, check red wire and fusible link L for open.
4.
If lamp illuminates in steps a, b and c, disconnect coolant fan relay connector and connect fused jumper between terminals 1 (red) and 4
(black/red). If coolant fan runs, replace coolant fan relay.
5.
If coolant fan does not run, leave fused jumper connected as in step 4, disconnect coolant fan connector and connect test lamp between terminals
as follows:
a. Connect between terminal B (black/red) and ground. If lamp does not illuminate, check black/red wire for open.
b. Connect between terminal B (black/red) and A (black). If lamp does not illuminate, check black wire for open.
c. If lamp illuminates in steps a and b, replace coolant fan.
Coolant Fan Runs Continuously
1.
With ignition switch in RUN position, disconnect coolant fan relay connector and connect test lamp between terminals 5 and 2.
2.
If lamp does not illuminate, replace coolant fan relay.
3.
If lamp illuminates, check dark green/white wire for short to ground. If wire is satisfactory, problem is ECM related.
