i found one unique maybe rare cause for the squeak that i had to deal with. the horn button brass piece was rubbing at certain points while turning the wheel. It was simple fix. Take the steering wheel off and with very fine sandpaper smooth out imperfections and it solved this problem in 5 minutes or so. may not be your problem but something to check.

91 Montero LS "Sandstorm", Auto, Dual Bouncy Seats, 2" Suspension lift, 2" Body Lift, GENII front IFS, 32" MT tires

89 Raider "Trailbreaker", 3.0, Auto, Dual Bouncy Seats