1997 dodge dakota with the 318 ....ok so i pulled the oil pressure switch and installed a mechanical gauge just to verify oil pressure....have ok pressure...so i put my oil pressure switch back in and now the dash gauge doesnt move. so i go to parts house and buy new one and replace....still nothing.. i have run all the wires down and all seem to be ok.....help what happened....also so if i permanently install a mechanical what do i do to get check gauges light to go out. thanks guys

 

Id put a Tee in there and run both the factory gauge and the aftermarket mechanical one. Don't run that crappy plastic tube that comes with though, get some copper tube.
easy to do the fittings are 1/8" NPT