The oil pressure switch on the 3.0-liter V6 in your 2002 Mazda B3000 truck not only provides the pressure reading for the gauge in the instrument cluster but it also sends information to the engine’s computer. The switch is an important tool that allows the computer and the driver to monitor the condition of the engine while it is running. A sudden loss of oil pressure will cause catastrophic failure of the engine and could damage other parts of the truck as well.
Locate the oil pressure switch on your 3.0-liter engine by locating the transmission dipstick near the back of the engine on the passenger side. Slide your hand in between the dipstick and the engine block. The switch is right at the top of the engine.
Press the locking tab in on the wiring harness connector on top of the pressure switch, then pull the connector loose and set it aside. The area is cramped but it can be accessed with a little effort.
Remove the oil pressure switch from the engine with a 1 1/16-inch socket and a ratchet, turning the switch counterclockwise. Pull it out of the block and discard it. Install the new switch in the hole on the block, then tighten it with the socket and ratchet until it is snug. Turn it about one-eighth of a turn more to secure it.
Connect the wiring harness connector to the top of the new switch and push it on until you feel it click or lock into place. Start the engine and verify that the switch is sending information to the gauge on your dash.
