Sending Units (Resistance Check)
Most models have a combination temperature sending unit (a resistance sender and temperature switch). Smaller terminal is resistance sender. Sending unit temperature values are stamped in sender body.
Connect test resistor between sending unit wire and ground. Turn ignition on. Check gauge readings and compare to specifications. See COOLANT TEMPERATURE SENSOR RESISTANCE table. Remove sending unit and check resistance at position or temperature specified. If resistance is not to specifications, replace sending unit.
COOLANT TEMPERATURE SENSOR RESISTANCE
| Part No. & Temperature: °F (°C) | Resistance: K-Ohms (X) | |
|---|---|---|
| 0-280-130-023 | ||
| 68 (20) | 2.1-2.9 | |
| 176 (80) | .27-.4 | |
| 0-280-130-026 | ||
| 68 (20) | 2.2-2.7 | |
| 176 (80) | .3-.36 | |
COOLANT GAUGE RESISTANCE
| Model & Temperature: °F (°C) | Resistance/Ohms (X) | |
|---|---|---|
| 325 Series | ||
| 105 (40) | 287 | |
| 140 (60) | 132 | |
| 151 (66) | 112 | |
| 158 (70) | 96 | |
| 176 (80) | 68 | |
| 198 (92) | 49 | |
| 216 (102) | 36 | |
| 249 (115) | 25 | |
| 262 (128) | 18 | |
| 528, 535, 635 & 735 Series | ||
| 105 (40) | 287 | |
| 142 (61) | 127 | |
| 249 (115) | 25 | |
| 262 (128) | 18 | |
TESTING FUEL GAUGE RESISTANCE
| Gauge Reading | Resistance Ohms (X) | Needle Position (From Horizontal) | |
|---|---|---|---|
| 325 Series | |||
| R | 71.7 | 0 Degrees | |
| 1/4 | 55.2 | 11 Degrees | |
| 1/2 | 30.1 | 42 Degrees | |
| 3/4 | 12.7 | 69 Degrees | |
| F | 3.2 | 82 Degrees | |
| 528, 535, 635 & 735 Series | |||
| R | 71.7 | 0 Degrees | |
| 1/4 | 59.2 | 19 Degrees | |
| 1/2 | 25.7 | 56 Degrees | |
| 3/4 | 13.0 | 70.5 Degrees | |
| F | 3.2 | 82.5 Degrees | |