Dieselburns, I just fixed my same turn signal problem by replacing the flasher with a new generic one from NAPA. (P/N NP552, $3.29) The first time I tried to fix it I used one pulled from a junkyard 1990 Montero, but it didn't make any difference. Either it was a weak design to start with or time had aged the components to the point where they didn't work well anymore.

1990 Monty LS 3.0 A/T LWB. KYB front shocks, OME rears and coils. 33x10.5 BFG Muds. 5.29, 2.85, RD110, RD46. 2 bouncys. Aisins. Monte Disco swaybar disconnects. GenII t-arms, idler arm, UCA's, V45W front brakes. 2in BL.