I got to say Thank You to @dripley ...

 

He's taught me something today which I've got to pass along to all you. The 2002 Dodge Ram truck have only a 1 wire oil pressure sensor. The wiring diagram is incorrect for the 2002 trucks and does NOT have the Orange or the Black/Light Blue wires. Now looking at the 2001 and 2000 model years are 3 wire oil pressure sensors. I've even gone down to my truck and checked and sure enough only one wire the black/light grey. 

Edited October 8, 20186 yr by Mopar1973Man

I beleive the 1 wire setup was a tsb update wasn't it?  

@dripley mention the same thing about a TSB...

point being if you have a 2nd gen you should verify what you actually have before doing anything involving fixing etc

At least I could verify this one. I went through RockAuto part listing for 2000, 2001, and 2002 Dodge Ram and the only year that changed was the 2002 Dodge which is a single pin oil pressure sensor. The only thing I can assume is that the ECM is still the standard 5V signal to the sensor and the ground reference is from the block itself like the older 1970's Dodge oil pressure sensors. 

I remember seeing and reading the TSB. What I remember is the switch activates around 6 psi of oil pressure and then the ecm takes over with ECT and RPM to register a set pressure. That is as long as IIRC.

One wire makes it a switch , right . Gauge always reads the same . My 99 is  3 wires and will read actual pressure , or as good as the gauge and sensor dodge uses

 My 04 Jeep grand Cherokee that I just bought to drive with my truck down  has a one wire switch , and the sensor went out leaving me with CEL, buzzers  and zero on the gauge , un easy feeling , I looked at putting in a t at the sensor with an aftermarket sensor and gauge leaving the stock setup in place

Have to Chime in here.  Just a side note.

 

I just purchased a ODBLINK XL at Mopar1973Man suggestion.  I was impressed when I set the Boost gauge up on the Android screen and it read 14 PSI with the engine off.  Seeing that I am 60-70 feet above sea level that is pretty dead on.

 

I was going to diagnose my intermittent Oil Pressure Gauge on my 2001 but after looking at the loom I think that I will wait for the started to take a break and then work on the loom from below.

 

Michael