Hello all, first time user here, so sorry if I'm posting in the wrong spot...
1989 Ford Ranger with 2.9L V6

As the title says, the rear antilock warning light has been coming on somewhat sporadically. Last time it came on, I topped off the transmission fluid and it went away. I'm not sure if that was just a coincidence or not, but there is a small transmission fluid leak and it was low. It came on again yesterday and it remains on even with the transmission fluid up to level. The odd thing to me is that when the light comes on, the blinkers stop working. They don't blink really fast like they do when a bulb is out, they just don't do anything. As soon as the antilock light goes off, the blinkers come back. This has me thinking it may be a grounding issue that they share in common? I've read about the antilock sensor on top of the rear differential, which I plan to inspect and clean shortly. I also remember cleaning the signal grounds before, but thought they were up in the signal housing? Probably worth mentioning that all the brakes components have been replaced in the past year and are working as they should. Any suggestions would be greatly appreciated!