I have a weird problem that needs to be fixed asap...wonder if anyone's heard of it. So the turn signals work normally in the front, but in the back...both signals flash (like hazards) when I activate the right or left signal. I can't find anything online and the computer is giving us a "nothing is wrong" code. The hazards work as normal when activated. I already replaced the turn signal switch and flasher relay and all wiring seems to be correct...any ideas?

1995 Chevy G20 5.7L RWD

 

Start with the bulbs. The 1157 bulbs that have 2 filiments inside one for parking lights and one for turn signal. If one break off and touches the other it can cause weird problems. Also make sure they are the right bulbs and in correctly.
Also bad grounding can be an issue too....make sure the sockets are not coated with rust.
Won't be a computer issue....

 

Maybe look to see if the van was built with the trailer option and the wires are tucked somewhere that they are touching each other