TCI Control Unit Tests

1. Check power supply for TCI control unit.
a. Check voltage between terminals 2 (+) and 4 (-) on disconnected control unit plug. With ignition on, battery voltage should be present.
b. Check voltage drop between terminal 2 on control unit plug, and battery negative.
c. Check voltage drop between terminal 4 on control unit plug, and battery positive.

2. Check closed circuit current for TCI control unit.
a. Connect ammeter in series on ignition coil (terminal 15).
b. Turn on ignition.
c. Ammeter should show zero amperes after approximately 1 second.

3. Check control unit ground.
a. Disconnect plug at control unit.
b. With ignition on, check for continuity between terminal 31 of control unit (not the plug), and ground. Resistance should be about 0 Ohms.
c. If resistance is excessive, repair wiring as necessary.

4. Check control unit output.
a. Connect an ammeter in series on ignition coil terminal 15. With engine running at 1000 ± 50 rpm, 1.7 - 7.0 amperes should be indicated.
b. If amperage is low, eliminate contact resistance.
c. If amperage is high, replace ignition control unit.