Removed plate from under car in front of rear tire, I found that the vacuum cap on the gas tank was dry rotted. I replaced the cap and it was stopped leaking.
On your 1996 DODGE TRUCK RAM 1500 1/2 TON 2WD, the OIL PRESSURE SWITCH is: UNDER HOOD, CENTER, REAR ENGINE AREA, PASSENGER SIDE OF DISTRIBUTOR, MOUNTED IN ENGINE BLOCK You can find this stuff at autozone.com under component location.
Under vehicle, passenger side, below seating area, passenger side of transmission, mounted on frame in fuel line.
On the 3.7L it is located under hood, passenger side, lower engine area, mounted in oil filter adaptor. On the 5.2 & 5.9L it is located under hood, center, rear engine area, passenger side of distributor, mounted in engine block.
Open the hood, look on the passenger's side, behind engine, under the cowl area.
The air is drawn from the grill area, below the windshield, by the passenger side wiper blade.
Under vehicle, passenger side, below seating area, passenger side of fuel tank, mounted on frame in fuel line
Check for a broken vaccum line near or under the driver side battery area.
Under hood, passenger side, lower engine area, rear of alternator, mounted in fuel line.
FRONT SEATING AREA, CENTER, PASSENGER SIDE OF STEERING COLUMN, MOUNTED IN FRONT OF CONSOLE.
Under hood, passenger side, rear engine area, mounted on upper rear of engine
The area where the driver's left foot would rest and the area where the passenger's right foot would rest
Front seating area, center, behind dash, mounted below passenger side of stereo.