Circuit Tests

Fig. 12 ETACS Control Unit Terminal Identification:

Power Supply & Ground Circuit Test

1. Ensure battery voltage is present at ECU connector 36 at all times.
2. Ensure continuity exists between ECU connector terminal 29 and ground at all times.
3. Ensure continuity exists between ECU connector terminal 30 and ground at all times. Fig. 12.

Ignition Switch Input Circuit Test

1. Ensure terminal voltage is zero volts at ECU connector 7, with ignition switch in ``OFF'' position and battery voltage is present in ``ACC'' position, Fig. 12.

A/INT Switch Input Circuit Test

1. Ensure terminal voltage is 5 volts at ECU connector 10, with wiper switch in ``OFF'' position and zero volts in ``AUTO'' position.
2. Ensure no continuity exists between ECU connector terminal 10 and ground, with wiper switch in ``OFF'' position.
3. Ensure continuity exists between ECU connector terminal 10 and ground, with wiper switch in ``AUTO'' position, Fig. 12.

Intermittent Variable Volume Switch Input Circuit

1. Ensure terminal voltage is 0-2.5 volts at ECU connector terminal 1.
2. Ensure continuity between intermittent variable volume switch connector terminal 1 and ground. Resistance should be 0-1000 ohms, and should change with movement of the intermittent variable volume, Fig. 12.

Vehicle Speed Sensor Input Circuit Test

1. Ensure terminal voltage is zero volts at ECU connector terminal 4 to ground with vehicle speed sensor On.
2. Ensure terminal voltage is 8 volts at ECU connector terminal 4 to ground with vehicle speed sensor Off, Fig. 12.
3. Connect ohmmeter between ECU connector terminal 4 and ground, then check conditions as follows:
a. Raise and support front end of vehicle.
b. Rotate tires in a forward direction.
c. Continuity should exist as wheels are rotating.

Wiper Relay Activation Circuit

1. Ensure terminal voltage is zero volts at ECU connector terminal 27, with wiper and ignition switch Off.
2. Ensure battery voltage is present at ECU connector terminal 27, with wiper switch ``OFF'' and ignition switch in ``ACC'' position, Fig. 12.

Washer Switch Input Circuit Test

1. Ensure terminal voltage is zero volts at ECU connector terminal 35, with washer switch Off and ignition switch in the ``ACC'' position.
2. Ensure battery voltage is present at ECU connector terminal 4, with washer switch On and ignition switch is the ``ACC'' position, Fig. 12.