[78magnumxe]

well it's a '84 w150 for one thing the little in dash light for the right turn signal doesn't work, but the left does. a while ago i lost tail lights, all turn signals, markers and dash lights. traced that back to the trailer plug being corroded, so cut the wires and taped them apart. then i had everything working (except that stupid in dash blinker light ) and then it blew a fuse and everything went back to the same so i put a 20 amp fuse in (supposed to be 15 but i only had 10 the first time) and then everything works. but now i have no tail lights markers or cluster lights ( but i have the left in dash blinker light and the high beam indicator) and the headlights brake lights and all signal lights. so i am running out of ideas short of ripping it all apart and checking all the wires. any help would be appreciated

 

[Smokey]

Well, you could start by replacing the light switch, eliminating that possibility right off.... but I fear that it may come down to wire chasing,... a tedious, but sometimes necesary task. Have you inspected the "cannon plug" where the whole harness passes through the firewall? Very often those slip fit connections corrode...

I'd reckon that the missing turn signal indicator light is a dead bulb... pul the instrument cluster out of the dash and install new bulbs in all the sockets, and check the contacts where the socket click in...

 

[Chump]

If this was a factory installed trailer package than you may have a relay under the dash that feeds off the headlight switch. I'm not sure where it is. All of the things you mentioned except the turn signal bulb get their power from the headlight switch.