Actually there's two issues.
1996 b3000
1 the dash lights and tail parking lights don't work, I've heard this may be a headlight switch issue or the dimmer switch.
headlights and front marker lights work, also turn signals work front and rear as do brake lights, except on rear pass side, see below
Any ideas??
2 my passenger brake light doesn't work, it's not the bulb, so I figure it's bad at Union between drivers/pass wires or connector is bad on passenger side??
Thanks for any help

 

Welcome to the forum

1996 Ranger most likely has a parking light relay if you have keyless entry(fobs)
If not then no relay

First check fuse 3(15amp) in cab fuse box, it powers parking lights and dash lights, also test if fuse 3 slot has 12volts with test light or volt meter, it should have 12volts all the time, not a key ON circuit
If its OK then pull out Fuse 7(7.5amp) in cab fuse box, it powers dash lights, IF......park lights are on, test it slot has 12v park lights on

If fuse 7 doesn't have 12volts with park lights on, and fuse 3 is OK, then yes its probably the main light switch, not dimmer switch since that wouldn't effect Park Lights

If you have keyless entry then do the above tests and then you will need to find the Park Light relay under the dash as it could be the issue instead of main light switch


On a 1996 there are separate Turn signal bulbs in the rear, this is important since tail light wiring is different, than on other years
There is only 1 brake light wire running to the rear of the truck, a Light Green wire, on the drivers side
If drivers side brake light works, then yes, the issue with passenger side brake light will be a local problem at the rear of the truck
The passenger side bulbs share a common ground so if other tights are working, like turn signal, then its most likely not a ground issue

DIY trailer light wiring can be the cause of most tail light issues, so if there has been a trailer light connectior installed give those connections a good look

 

WellNo luck so farI tested the #3 and #7 fuses theyr ok, replaced headlight switch still no luck.
dash lights and taillights don't work!
What else could it be?
It seems that if any wires are cut going to taillights that wouldn't affect dash lights?
And same if wires to dash are cut then taillights may still work?
Checked fuses in fuse box under hood too, they are getting power.
Again, headlights and front parking lamps work, turn signals work, brake lights work, but no tail lights and no dash lights.
Any help appreciated!

 

Check Maxifuse #7 in Engine bay fuse box, 20amp, full time 12v
It sends 12v to Fuse #3 in cab fuse box, 15amp, full time 12

Battery 12v-----------fuse #7(engine)---------------------fuse #3(cab)------------(park light relay)---------main light switch-----out to park lights and Fuse #7(cab)dash lights

If front park lights work then fuse in engine bay and fuse #3 in cab are OK, and so is the Main Light switch.........but
There is a 5 wire splice near the main light switch, as far as I can tell, where the the Brown wire comes out of the main light switch and feeds 12v to............
Front bulbs
Rear bulbs
Dimmer
GEM
On 4 separate wires, so with 12v IN that's 5 wire splice

Diagram below but doesn't say where the Splice is, you would need a 1996 Ranger EVTM for that location
You can look on the back of the main light switch connector, that's where the Brown wire comes out, and there may be more than 1 brown wire on that one terminal, each supplying 12v to one of the 4 sub-wires