the compessor clutch cycles on and off every few seconds not allowing the system to…
Where is the oil pressure switch, I cannot find it on my 1990 Ford Ranger 2.9L engine?
NOTE: Oil pressure senders are used for oil pressure gauges, whereas the oil pressure switches are used for vehicles equipped only with a low oil pressure warning lamp.
The oil pressure senders/switches are located as follows:
- 2.3L engine — left, rear side of the engine, in the cylinder head
- 2.9L and 4.0L engines — front left side of the engine, below the cylinder head in the engine block
Oil Pressure Switch Testing
- To test the oil pressure switch, open the hood and locate the switch.
- Disconnect the wire from the switch. Attach one end of a jumper wire to the terminal on the end of the wire, then touch the other end of the jumper wire to a good engine ground (any bare metal engine surface). Have an assistant observe the instrument gauge cluster while you do this and tell you if the low oil warning lamp illuminates or not; the low oil warning lamp should illuminate.
- If the lamp does not illuminate, skip to Step 3.
- If the lamp does illuminate, replace the switch with a new one.
- Before jumping to any bad conclusions, try a different area for grounding the jumper wire on the engine. If the lamp still does not illuminate, touch the jumper wire end to the negative (-) battery post.
- If the lamp illuminates, the problem lies with the engine not being properly grounded.
- If the lamp does not illuminate, skip to Step 4.
- Connect the original wire to the oil pressure switch. While sitting in the vehicle, turn the ignition switch to the ON position without actually starting the engine. Observe the other lights on the instrument cluster.
- If all of the other lights illuminate when turning the ignition switch ON, the oil pressure switch is defective and must be replaced.
- If none of the other lights illuminate, there is a problem with power supply to the instrument cluster and gauges.
Oil Pressure Switch Removal
1.Disconnect the negative battery cable.
2.Disconnect the wiring at the sender/switch.
3.Remove the oil pressure sender/switch from the engine.
4.Coat the threads with electrically conductive sealer and thread the unit into place. Tighten the sender/switch to 10–18 ft. lbs. (13–24 Nm).
5.Attach the wiring to the sender/switch and connect the negative battery cable.