94 Dodge Ram 350, 5.2 engine. On a recent road trip, Oil gauge reading became erratic - low then high then low. Oil level good; engine temp good. I changed the oil pressure sending unit (easy on a van). Oil pressure reading stabilized at normal on return trip home. Whew! However, NOW the oil pressure reading does not return to low when you cut the engine off and the 'red light' does not appear when the ignition switch in on, but not started. Do I have a gauge problem or was the replacement sending unit possibly bad? Any ideas appreciated.

 

First off, are you positive you installed a sender for a gauge and not for an idiot light?

 

I installed the oil pressure sending unit called for.. has two connections on top that the connector fit. Thats as sure as I know to be. Thanks.

 

With the key in the on position, short each of those two wires (one at a time) to ground. One will turn on the idiot light, and the other should make the gauge pin all the way over. If the light comes on and the gauge pins, then you got a bum sensor. If it doesn't happen the problem will be in the wiring, the bulb is blown, gauge is broken, or a fuse is blown.

 

Thanks. I will check the light wiring.