Took my 99 Ram 1500 for the emission test and it failed due to no voltage to the OBD port. Any suggestions on what to look for and how to test for voltage to the port?

find a wire diagram and start shooting wires to find the problem. I'd start first AT the OBDII port, check the back side of it for loose or broken wires.

check the fuses

i have had few do that, ck the wiring and obd connector.. also check it with a scan tool just to see if it will connect.. clean the connectors as well.. look for broken,dirty bent pins.. find a wiring diag and find out what wire powers the obd up.. i had a kid use that pwr wire from the obd connector to run is radio.. good luck..

check fuse for cigarette lighter/power port. Very common that the OBD2 port is powered thru the same fuse.

I found that the wire that goes to the factory radio is also pink same as the OBD power wire. Both have no power and the fuse has power on both sides. I ran a jumper wire to the pink wire to send power to the obd port and it passed emissions then. It was about a year the ago the radio power feed quit working. I just ran a different wire to power the radio. Maybe next winter when it is cooler out I will try to trace it down, too hot here in AZ to mess with it now. Truck runs great as it is. Could be a bad connection not much left of the plastic inner dash. The AZ heat has made it so brittle that pieces fall out of it. None of the switches have any thing to mount to, can not even put the ash tray in so much is missing and no support.