Tail lights and dash lights out, headlights still work. Bad switch?
 

I have a 98 Montero 4wd and recently the taillights cut out as I was pulling a trailer. The brake lights and parking lights went out along with all the dashboard, I realize they are all part of the same circuit.

Im assuming I have a short somewhere, I checked the fuse under the dash and it its ok and I also checked the relay under the hood. Both dont seem like the culprit. In the meantime I tapped the power from the rear AC adaptor line directly to the taillights and ran a switch to it. When I switch on the alternate power to the taillights I get the parking lights and dash lights all to work, which will allow me to drive the car at night for now.

Is this a problem of the switch in the steering column? Would changing this solve my problems? Extra bonus if you could tell me the part number.

Many thanks!