I have been unable to correct a turn signal problem in my 98 Tacoma. When I step on the brake pedal, the left turn signal bulbs light and the left turn indicator arrow lights. If I put the left turn signal on, both the front and rear signal lights operate properly. If I step on the brake pedal while the turn signals are on they stay lighted as though they were brake lights, but they blink slightly.
I have changed all the bulbs. All the 1157 bulbs work in both modes. I'm stumped. Any ideas would be appreciated.