Component Tests and General Diagnostics

Fig. 21 Testing Double Terminal Thermo Sensors:

Thermo Sensors

1. Drain cooling system, then remove thermo sensors from radiator.
2. Submerge sensor end of thermo sensor as shown in Fig. 21.
3. Connect ohmmeter across thermo sensor terminals.
4. On Eclipse models, continuity should exist at approximately 180-185°F, and no continuity at 172°F or less.
5. On 3000 GT models, the radiator fan motor thermo sensor should have continuity between sensor terminals when water temperature reaches approximately 178-192°F.
6. On 3000 GT models, the condenser fan motor thermo sensor should have continuity between sensor terminals when water temperature reaches approximately 196-210°F.

Fan Relay

Fig. 27 Relay Terminal Identification. Diamante, Eclipse & 3000GT:

1. With radiator fan relay disconnected, use suitable ohmmeter to check for continuity between terminals 2 and 4 Fig. 27, continuity should exist. Check for continuity between terminals 1 and 3, continuity should not exist.
2. Apply battery positive voltage to terminal 2 and battery negative to terminal 4, then check for continuity between terminals 1 and 3, continuity should exist.

Resistor Check

Fig. 28 Resistor Terminal Identification. Eclipse:

Fig. 29 Resistor Terminal Identification. Diamante & 3000GT:

1. On Eclipse models, disconnect connection from resistor, then measure resistance between terminals 1 and 2, as shown in Fig. 28.
2. Resistance should be between 0.26-0.32 ohms.
3. On 3000 GT models, measure resistance between terminals 1 and 4, as shown in Fig. 29.
4. Resistance should be between 0.29-0.35 ohms.

Radiator Fan Motor

Fig. 30 Radiator Fan Motor Terminal Identification. Eclipse & Exop:

Fig. 31 Radiator Fan Motor Terminal Identification. Diamante & 3000GT:

1. Disconnect fan motor connection.
2. Connect battery to terminals as shown in Figs. 30 and 31. Motor should operate smoothly.

Condenser Fan Motor

Fig. 32 Condenser Fan Motor Terminal Identification. Eclipse:

Fig. 33 Condenser Fan Motor Terminal Identification. Diamante & 3000GT:

1. On Eclipse models, disconnect fan motor connection.
2. Apply battery positive voltage to terminal 3 and battery negative to terminal 4, Fig. 32. Motor should operate smoothly.
3. On 3000 GT models, apply battery voltage terminal 3 and battery negative to terminal 4 as shown in Fig. 33, motor should turn.
4. Apply battery voltage to terminal 1 and battery negative to terminal 2, motor should turn.