Welcome dieselburns! Ditto 89isMine's advice; it's spot on. But replacing the turn signal relay may not make much of a difference--it didn't fix mine. Lots of Gen1 folks have exactly the same symptoms as you. Some have suggested it might be symptomatic of an alternator about to go, or a weak ground. If you do figure it out, please post! I'd love to get rid of that annoyance.

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.