You did the full on FSM cruise control diagnostics mode where you check a few things with the engine off, and then go for a drive? And the light flashes various patterns in response?Hmm...1991 Cruise control does not work. Light works fine. Diagnostics shows OK.
Just to be extra clear: Speed sensor is tested by driving while in diagnostics mode. Light should be steady on below 25mph, and flashing regularly above 25mph. Anyway, if you still suspect it, pull it and see if it's fouled with gear oil from the transfer case. If it is, cleaning it up may get it working. If that's the case, all you need is a new o-ring seal.Did diagnostics. Toyota mechanic did diagnostics. No problems. There are a couple of items that could be inop and diagnostics shows everything OK according to my mechanic. cdan, how much is a speed sensor?