Control Module Circuits

Main Feed Connector:

There are three wiring harnesses connected to the electronic control module:
^ The eight-wire pigtail harness connector
^ The five-wire harness connector
^ The eight-wire harness connector
To check the integrity of these circuits, disconnect harnesses from the electronic control module and perform the following checks:


EIGHT-WIRE PIGTAIL HARNESS CONNECTOR

Eight-wire Pigtail Harness Connector (Electronic Shift) C302:

1. Connect a voltmeter between terminal eight and ground. Voltmeter should indicate battery voltage.
2. Connect a voltmeter between terminal seven and ground, then turn ignition switch to Run position. Voltmeter should indicate battery voltage.
3. Connect an ohmmeter between terminal 6 and ground. Ohmmeter should indicate less than ten ohms resistance.
4. Connect an ohmmeter between terminals four and five. Ohmmeter should indicate less than ten ohms resistance.
5. Connect an ohmmeter between terminal three and ground. Ohmmeter should indicate zero ohms.
6. Connect an ohmmeter between terminal two and ground. Ohmmeter should indicate zero ohms.

EIGHT-WIRE HARNESS CONNECTOR

Eight-wire Pigtail Harness Connector (Electronic Shift) C301:

1. Connect an ohmmeter between terminal one and ground, if vehicle is equipped with a Manual Transmission (M/T), DEPRESS clutch pedal. Ohmmeter should indicate less than 50 ohms resistance. If vehicle is equipped with an Automatic Transmission (A/T), shift transmission into NEUTRAL. Ohmmeter should indicate less than 50 ohms resistance.
2. Connect an ohmmeter between terminals two and three.This will check continuity of speed sensor that is located in the transfer case. The speed sensor picks up rotating speed of the output shaft from two notches that are cut in opposite sides of the outer ring of the clutch housing assembly. Ohmmeter should indicate between 200 and 350 ohms.

Checking Ohmmeter Reading For Shift Motor Position Sensor (Electronic Shift):

3. Connect an ohmmeter between terminal eight and terminals four, five, six and seven respectively. Refer to chart for appropriate ohmmeter readings in each transfer case position.

FIVE-WIRE PIGTAIL HARNESS CONNECTOR

Fig. 7 Five-wire Pigtail Harness Connector (Electronic Shift) C300:

1. Connect an ohmmeter between terminals one and two, then DEPRESS 4x4 (2H-4H) switch. Ohmmeter should indicate less than 50 ohms of resistance while switch is being depressed.
2. Connect ohmmeter between terminals one and three, then DEPRESS low range switch. Ohmmeter should indicate less than 50 ohms of resistance while switch is being depressed.
3. Connect a test lead between terminals 1 and 3, then turn ignition switch to RUN position and observe indicator lights. Light in instrument panel and low range bar should illuminate.
4. Connect a test lead between terminal 5 and ground, then turn ignition switch to RUN and observe indicator lights. Lights in instrument panel and 4x4 bar should illuminate.