What Could Cause Sparking When Connecting Brake Controller Directly to Battery

Question:

I have read a recent posting and reply by an expert. The issue was that the unit is not lighting up when the key is on. I have used my unit a few times out with the RV. I hook directly into the 7 pin connector on my 2015 Chevy 2500 HD. It worked great out of the box. I recently noted it not lighting up at all with the trailer not attached and displays an orange screen. On the advice of the expert, the customer was told to use the pigtail with blunt wire ends and place the white to the ground negative terminal on the battery and the Black to the positive side of the battery. I did this but was surprised to have the wires attempt to fuse the terminals? Is this normal? I did see the screen momentarily light up. I was bit concerned of damaging the P3 based on the fact that it did blink at me. I am correlating an event with the loss of power to the controller: I launched my boat recently and by habit, added the 7 pin to 4 pin trailer adapter. I did not notice any issue with the controller, but I dont believe I would have looked at it based on the different trailer. Now, of course, during launch, the trailer is unplugged from the truck to save the trailer lights. I am wondering if this marrying of the adapter and any presence of water could cause an issue with the truck system or the controller. Its the only thing that may have caused change. So, firstly, the wires touching the terminal seem to burninch truck is not running What would cause this reaction to the terminals? And did something with the launching cause an issue? Hope you can help. Thanks

asked by: Paul T

Expert Reply:

Did you for sure run the white wire to the negative post and the black wire to the positive post? It sounds like you may have ran them backwards based on the arcing you mentioned. If you have verified the correct wires to the correct posts you most likely have a bad controller with an internal problem.

While it's a good practice to unplug trailer wiring before backing a trailer into water there are quite a few people who do not do this without any issue at all. I'd suspect your experience with this would not be an issue.

expert reply by: Jameson C