Despite the local indication of the U-haul store and thier computer lookup, the basic $16 taillight converter, (and others, I'll presume) when installed caused the symptons you describe in my own installation. My investigation revealed an indication that because the 2006+ model year RAV4 uses LED tail lamps that the basic converter is enough of a draw(?) to convince the dash sensors that that you've got an ABS problem.
To be specific, I noted that it was actually using the turn indicators but not the running lights or brake lamps that caused the dash sensors to indicate error. I went back to U-haul to question them about the frequency of defective converters, but quickly concluded from the shrugging shoulders of the counter person that that wasn't worth the effort.
Long story short, the resolution was to use a powered converter, like $40 U-haul #13493 (
U-Haul moving supplies: Trailer Light Power Module) and tap the power from the back side of the 12v power plug in the rear cargo area.
Hope this helps....
Hitch Wiring Problem 2006
Linear Mode
