I'm no electrician which probably explains why I couldn't fix my old switch.
But like I said that was the exact same problem I had on my 96 xlt .
My switch is the 4 way toggle with a 3 position selector above . (1/left - left mirror).. (2/middle -nothing) and (3/right - right mirror) left mirror worked perfectly but when I switched to right mirror only the up and down worked , no side to side.
When I took the switch off and apart there was a really bizzare configuration ( like I said I am no electirician) and i tried jumpers and shorting across different contacts and could never really understand the way it was wired.
I felt like I tried everything and figured that the switch I found here from a guy who was parting an explorer out and would sell and ship to me for 18 dollars was money well spent . When the switch arrived I checked that mine was still not working( it wasn't) and changed them out and BINGO both mirrors worked.
If you decide to try it and can't find any switches write back and I'll dig up the info I can on the guy here who sent me the switch . it seemed like he was parting out a lot of explorers.
hop this was a little help
cheers
Tony