wiring plug adapter between truck and chipper

[outdoorsman0490]

My chevy 3500 chip truck has the conventional 7 prong wiring harness on it. My brush bandit 990 has their conventional 6 prong wiring harness on it. Everything was fine until my adapter for them cracked from the cold, inside the truck, the dash kept flashing "check trailer wiring" and "trailer connected" just about non-stop. I went to the auto parts store and picked up another adapter. When I plugged the new one in, the trailer brakes on the chipper engaged when I tried pulling away. I went back into the store and picked up the 7 prong to 6 or 4flat adapter and tried it (this style was what my original one was); this did the same thing, brakes engaged. I ended up driving back to my lot and tried the 7 to 6 that is on my stump grinder, it as well did the same as these other new ones.

You can tell it is the adapter because when I pull forward and feel the chipper holding me back, I can put the parking brake on, go into park, and when I go to the back of the truck and pull out the adapter, you can see the brakes let go on the chipper. How is it that the old adapter does not cause this, while the other 3 I tried all engage the brakes. It is the same brand that made all 4.

Has anyone ever seen or heard of this happening. Until I figure it out, I am going to be running the old cracked one listening to the warning in the truck go on and off.

Thanks for your help

 

[outdoorsman0490]

all 4 were hopkins brand, that was what both of the local store carried

 

[outdoorsman0490]

Bump

 

[55chevyparts]

Seen it a couple of times, just open the adapter and correct the wiring. You can just swap around the connections inside.
Hopkins website shows a quick change plug on the new adapters to change settings.
http://www.hopkinstowingsolutions.com/doc/47570.pdf

 

[stihl023/5]

Either the adaptor or the trailer has a wire wrong.

 

[outdoorsman0490]

Thanks Chevy, took it apart and switched the blue and black wires, it is all good now.