Resistance Test (Miata)
- Remove instrument cluster. Apply 12 volts to terminal 2K, and ground terminal 2J of instrument cluster connector. See Fig 1 .
- Connect Red lead of Checker (49-0839-285) to terminal 2B of instrument cluster connector and Black lead to ground. Set checker to specified resistance values and ensure oil pressure gauge gives proper indication. See OIL PRESSURE GAUGE RESISTANCE .
- If gauge does not function as described, replace gauge. If gauge is functioning normally, repair wiring harness or sending unit. Measure resistance of oil pressure sending unit. With engine off, sending unit resistance should be 110-130 ohms. With engine running, resistance should be 13-55 ohms. Replace sending unit if not to specification.
OIL PRESSURE GAUGE RESISTANCE
| Ohms | psi | |
|---|---|---|
| Miata | ||
| 52 | 0 | |
| 41 | 30 | |
| 16 | 90 | |
| RX7 | ||
| Infinite | 0 | |
| 200 | 30 | |
| 110 | 60 | |
| 80 | 110 | |