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 on sender body.
Connect a test resistor between sending unit wire and ground. Turn ignition on. Check gauge readings and compare to specifications. Refer to the COOLANT TEMPERATURE SENSOR RESISTANCE table, COOLANT GAUGE RESISTANCE table or the FUEL GAUGE 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 Number/Temperature °F (°C) | Resistance k/ohms | |
|---|---|---|
| 0 280 130 023 | 68 (20) | 2.1-29 |
| 176 (80) | .27-.4 | |
| 0 280 130 026 | 68 (20) | 2.2-2.7 |
| 176 (80) | .3-.36 | |
COOLANT GAUGE RESISTANCE
| Temperature: °F (°C) | Ohms | |
|---|---|---|
| 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 | |
| 525, 535 & 735 | ||
| 105 (40) | 287 | |
| 142 (61) | 127 | |
| 249 (115) | 25 | |
| 262 (128) | 18 | |
FUEL GAUGE RESISTANCE
| Gauge Reading | Ohms | 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 | |
| 525, 535 & 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 | |