Cooling System: Testing and Inspection

Refer to SCHEMATIC DIAGRAMS/ELECTRICAL AND ELECTRONIC DIAGRAMS for wiring diagrams when performing the following procedure.

1. Check engine and bring to normal operating temperature.
2. Check fan motor electrical connector for proper engagement.
3. Connect diagnostic tool to connector, if fault code 88-12-35-55 is displayed, proceed to step 4.
4. With ignition switch in run position, test battery voltage at single pin connector at fan relay.

Fig. 25 SBEC 60-way connector:

5. If voltage reading is normal:
a. With ignition off, disconnect 60 way connector from single board engine control (SBEC), and return ignition to run position. Test battery voltage at cavity 31 of 60-way connector.
b. If voltage reading okay and female terminal is not damaged, replace the SBEC. If voltage reading is 0, repair open or short in circuit C27.
6. If voltage reading is 0-1 volt:
a. With ignition off, disconnect 60-way connector from SBEC, and return ignition to run position. Test battery voltage at single pin connector at fan relay.
b. If voltage reading is okay, replace SBEC.
c. If voltage is 0-1, test voltage at blue wire in 3-way connector of fan relay.
d. If voltage reading okay, replace fan relay. If voltage reading 0, repair open or short in circuit C27.
7. Turn ignition off, connect 60-way connector at SBEC and test system.