Well this is my problem...My 01 Astro came with the factory Installed trailer hitch package. But the electrical plug was not installed. So a while back i had to get one so that i can hook up a trailer from u-haul. So one of the guys there hooked me up with the plug. Great.... But every time i hook up a u-haul trailer it works....But for my boat......No..... When hooked to the boat trailer.... When I signal left or right It goes off like a hazard light when i brake it brakes.... when i hazard it hazards ..... I dont get it... I doubled checked the diagram...yellow w/ yellow brw w/ brw grn w/ grn Wht w/ large gauage white from the van...Am i messing something here pls help me anyone thanks...

 

My 99 also came with a factory hitch but without the trailer light plug system. This is not much help but I wonder why the factory would not provide the needed plug system.

 

i do not know what lights are on the boat trailer,but look at the ground's on the tail lights and might need a hd flasher for the van .