Hey guys got a 1994 ranger, when I push back the switch for the brights the lights go off and the dash lights go off and the voltage gauge drops, I’ve tested my battery and alternator are both good any help

 

Welcome to the forum

High beams and low beams both use the same fuse and main light switch and the Multi-function switch(turn signal stalk)
Only Low beams or High beams can be on at one time not both so if there is a problem when high beams are turn on low beams would be off at that time, so no headlights at all

But there is also "Flash to pass" on the multi-function switch, pull the stalk toward you and high beams will come on as long as you hold it toward you, this uses a different fuse and not thru main light switch, also has 12volts all the time, key on or off, main light switch on or off doesn't matter
But it uses the same High Beam wires out to the head lights

See if Flash to pass works without causing voltage to drop
It they work then not a problem in the head light wiring, from multi-function switch to bulbs
If Flash to pass also causes a voltage drop then its high beam wiring issue

If low beams are OK then Main light switch should be OK
So that just leaves the multi-function switch, an internal short
You can pull it out and test it with OHM Meter, or just replace it

 

I just tested the flash to pass thing it also makes the voltage drop so I’m guessing I have a short somewhere?

 

Yes

Most likely High beam wire, but where..................
There is just the one high beam wire, light green/black stripe wire that runs out of the multifunction switch and thru the firewall to the engine bay
It should run on driver side of engine bay to the front and then split behind drivers side head light to run over to passenger side

With it there should be Low Beam wire, red/black, a Brown wire(Park lights), and turn signal wires(white/blue and green/white)
Also a BLACK wire, which is the Ground for all the lights, but should not come from firewall would join the wires at rad support

Look at wiring harness's on drivers side for any obvious damage to the outside

You can unplug each head light, one at a time and try Flash to pass to see if either head light connector is shorted internally, that's where the 12v and ground meet, "officially"

There are no grounds in the multi-function switch, but then you are also not "blowing a fuse" which would happen with a dead short to ground, so up in the air as far as multi-function switch goes