Q: OBll CODE : P1899

Hi my van has a P1899 park neutral safety switch (aka "NSS") My van will start & turn over in any gear however its not started up though. Also I have no reverse lights to. the fuse panel in glove box keeps blowing the backup light fuse as well.. I've replaced the Neutral safety switch and still showed code so then I tested the 3 wires on the NSS with ohm meter and with a test light.It test all good. still have P1899 code. So I tested it all from the ignition switch to the starter relay, solenoid, and starter. No luck. I just learned that the Transmission range sensor (TRS) on my 1996 Dodge B2500 van can be faulty and can cause backup lights not to work and blow em again and again. I just cut the middle wire on NSS and grounded it to the frame of van thinking that would make mil light go off it did but the p1899 code comeback as pending. mil light will probably come back on soon. everytime i replace reverse backup lights they blow. So I'm leaning toward the TRS switch. So How do i test the TRS wires and the TRS switch? Thanks
Trans is automat 36rh