Oil pressure switch?

[SilveradoGuy85]

Have a 98 1500 with the 5.7 350. Sometimes when I'm driving the "check gauges" light on the dash lights up and at the same time the oil pressure gauge will go to 0. But, all I have to do is bump the gas and the light will go off and the gauge will read normal again. I'm just wondering if it could be the oil pressure switch. If so where is it on my truck (looked in my Haynes manual and couldn't find it) and how will I know if it's the 1 terminal or 3 terminal version? Is there a way to know without taking it off since I plan to drive my truck to the parts store. Thanks

 

[slippy3002]

Pull the code 1st, then you can determine if it is the switch.

Sent from ®obland!

 

[someotherguy]

There's no codes set for a "check gauges" light. That light comes on to warn you to look at the gauges because one of the important ones is reading outside of the expected range - low oil pressure, high coolant temperature, etc.

If your oil pressure gauge drops to zero and you don't hear any ticking, clattering, or knocking from the engine - then the most likely suspect is in fact the sender. It's at the top rear of the block, down behind the distributor, in kind of a sonofabitch place to get to.

It's been long enough that I've looked at one on a Vortec to tell you whether it's 1 or 3 terminals. I can't remember if they use the oil pressure switch as a redundancy on the fuel pump relay circuit or not. Quickest way to know for sure would be, climb up on top of the engine and shine a bright flashlight down there and look at the connector plugged into it. If you see 1 or 3 wires, then you have your answer. Probably have to pull back a little flex-loom to see the wires. Or, just unplug it and count the pins in the connector.

And, if it's screwed sideways into a brass 90 degree elbow like the TBI engines use, treat that thing like it's made of glass because if you just start wrenching on the sensor, the elbow will snap like a twig then you have to use EZ-outs to get the rest of it out of the block.

Richard