I have a 2001 ram 24v Cummins. 1 wire oil pressure switch/sening unit? The one wire to unit was unplugged by previous owner where does it plug into? Connector is on unit but single brown wire was tied around brake wires trying to get guage to work.

 

He must of had issues with a 5volt signal and traced it to the oil switch. That 5 volt loop has more then one sensor on it and could do weird things on how truck runs. 

It's only a single wire, just line it up with the pin in the sensor and it should be it. If you start having issues right if way, then that sensor is probably shorted out and you'll need a new one. 

If you just have a wire connection it is just a switch. It is not sender and would not have the 5v signal. My 02 is set up that way, only one wire. When the engine is started and near 6 psi it closes and the ecm takes over using ect and rpm s to show pressure. Does your pressure gauge work?

Not sure I have heard of this on an 01 though. @Dieselfuture is yours not a one wire switch? The 02 wiring diagram does show a 3 wire sender but mine and the spare engine wiring harness I have both only have one wire. I will get the spare harness and see if l can find out where it terminates.

Edited April 10, 20205 yr by dripley

4 hours ago, dripley said:

Dieselfuture is yours not a one wire switch? The 02 wiring diagram does show a 3 wire sender but mine and the spare engine wiring harness I have both only have one wire. I will get the spare harness and see if l can find out where it terminates.

Yes mine is one wire, I was thinking it was still using a 5v loop, guess not. So you're saying 2 wire is on the loop and single wire is not ?

6 minutes ago, Dieselfuture said:

Yes mine is one wire, I was thinking it was still using a 5v loop, guess not. So you're saying 2 wire is on the loop and single wire is not ?

Thats what I am thinking. Does not make sense to me to send a 5v reference with no to way to send a signal back. I figure it just grounds that wire to let the ECM know it has pressure so it can take over. Of course this the chicken man explaining wiring. That can be dangerous.

4 minutes ago, dripley said:

Of course this the chicken man explaining wiring. That can be dangerous.

I think you might of just graduated to a full grown turkey