Trailer Brake Not Connecting

Installed the REDARC tow pro elite yesterday on my 2018 TRD Off Road and when I plugged in my trailer, the controller did not pick up the trailer was connected. The lights all worked on the trailer, left/right/braking lights but upon a test drive, the brake controller did nothing to slow it down. We tested the READARC with a circuit tester at the blue wire and it lights up the knob meaning the device appears to be good. When I bought the truck, the previous own installed a custom bumper which did not include the blind spot monitor connections being reconnected. Could this be the cause of the problem or is there another possibility? The 7 pin does have all the lights work, just not the trailer brakes.

 

My new REDARC went out (stopped recognizing 7-pin) on my third trip out. Of course did all kinds of checking with the cables and wires in the dash. Be sure to clean the 7-pins and plug receptacle to be sure good contact with plug. I also checked the fuse under the hood. Removed it, placed it back in. Once I had done all these, the plug has been recognized since by the REDARC. So really don’t know which of the things I did worked regretfully, but so far so good after three more camping trips.

 

When you push the manual overide do you get the blue breathing response? If so it’s telling you that it can’t detect the trailer brakes and suggests you check the 7 way plug and connections. I think @gatriguy probably had it solved when he cleaned up the 7 pin connector.

 

Thanks guys. I've checked the trailer brake fuse and all good. the 7 pin looks clean and new but will check that for any loose wire in the back.

 

Give the plug pins a once over with a multimeter:

• Top right = 12-volt hot lead
• Middle right = right turn/brake light
• Bottom right = brake controller output
• Bottom left = ground
• Middle left = left turn/brake light
• Top left = tail and running lights
• Center = reverse lights

 

Figured out the plugin to the back of the 7 round/4 flat was burned out on the blue wire. Toyota said I need to replace the entire wiring harness at $1300. That seems ridiculous since I only need the plug replaced but they said they do not splice anything. Does that make sense?

 

It makes sense on their side but not on the side of "reason". The factory plug is apart of the original harness so they will state that the entire harness needs to be replaced. Buy a new 7 pin on Amazon and splice it in yourself.

 

Will it mess with other systems? One parts guy tried to tell me everything was connected and that's why they don't splice.