Oil pressure gauge not working

[Ue413]

Oil pressure gauge on M923 not working.......replaced sending unit and gauge with known working replacements and still nothing.

i assume it is a ground or wire issue, but not sure where to start.

when turn on key, the needle doesn't "bounce" like all the other gauges.

Any thoughts on what I need to do?

 

[simp5782]

Do you have the p2p program downloaded?

Should be # 27 coming into the gauge with power. Gauge should be grounded thru the dash. You should have power on #36 coming out of the gauge to the sending unit. It should have a ground off that. The resistor in the unit should regulate voltage to the gauge to adjust pressure correctly. Was the hold where the sending unit came out of clean? Not gunked up?

Also one time a wise old MV owner told me a story that there are such things as bad new parts.

Another note it to check your wire continuity on the wire from the gauge to the sending unit. and 99% of the problems on these trucks that I run into in the electrical world or even them acting goofy are all connection related. Keep a bottle of Stabilent 22 handy. Napa part number is CE1. It is like soldering connections together. Doesn't take much of the stuff.

 

[74M35A2]

A mechanical military one makes a beautiful replacement, looks stock, and works superbly better. Mine essentially follows my tachometer, even during upshifts.

 

[Ue413]

Thanks gents.....the gauge and sender were from working trucks....so I'm confident I've got an electrical issue. I won't have time until next weekend to keep digging, so I'll keep you posted.

74m35a2....have a brand on that mechanical unit? I've heard (and seen) how GI issued gauge works and on A2's, they don't seem to!

 

[74M35A2]

http://www.steelsoldiers.com/showth...chanical-Engine-Oil-Pressure-Gauge-Swapped-In

 

[jacklegjim]

The gauge is grounded through the bracket that holds the gauge in the dash.
make sure that it is tight or run a wire from the mounting nut to a good ground point.

 

[Ue413]

Thanks for the help and problem solved..... I wasn't grounding. Ran a wire and all good.

thank you for the insight and help!

 

[Cape Coastie]

Could always add a mechanical gauge as well. Great to have a back up that doesn't require power. Just remember to change the 12 volt bulb to 24 volt. It was really bright for a little while.