Troubleshooting "Short" Error Code On Curt Discovery NEXT Trailer Brake Controller C84VV

Updated 09/05/2026 | Published 04/08/2024

Question:

I’m installed Curt discovery next 51126 with quick plug electric wire harness 51455 on my Toyota Tacoma 2022. It is working but when I push manual control button display no trailer connected shows ‘Short’. I don’t understand why is it showing because my Tacoma is pre wired to this type brake controllers. I just want to know is it normal or not. If not how I can fix it . Thank you Serg

asked by: Serg

Expert Reply:

Hello Surg. It is definitely odd that you are seeing the "short" error code on the Curt Discovery NEXT Trailer Brake Controller # C84VV, especially since your Tacoma was pre-wired from the factory. Nonetheless, this error code is definitely not normal, and is an indication that something is wrong. The display should show the current gain setting when the manual override is applied.

With no trailer connected, the "short" code means that the red wire is connected to ground side of the stoplight switch or is shorted to ground. I suggest that you thoroughly inspect the brake control wiring. You will be looking for any damaged, pinched or frayed wires. Since your vehicle is so new we would usually suggest taking it to a dealership for service.

expert reply by: Jesse M

Bob

9/5/2026

Hello Jesse I just installed a Curt Discovery NEXT brake controller and was having the same problem as so many other people on your site as well as several other sites. The controller worked ok when pushing the brake pedal but when using the manual control the display showed a short. I read on your site that another fellow was having the same trouble but the fault went away when he removed the light bulbs. He said he was just going to ignore the issue as he felt that there wasn't really a short and perhaps the controller sensitivity was just too high. I have a 2002 Chev 2500 and it is hooked to my 5th wheel trailer. The trailer has LED stoplights but the truck stoplights are incandescent. I removed the left side bulb on the truck and the 'short' fault went away. I replaced the bulb and the fault came back. I removed the right side bulb and the fault went away. I replaced the right side bulb and the fault came back. Conclusion:... The incandescent bulbs have a low resistance and when in parallel the circuit resistance is halved indicating a short to the controller circuit. I replaced my truck stop light bulbs with LEDs and the problem was solved. LED bulbs have a higher resistance than incandescent bulbs so the controller does not see a short. The controller probably works ok with newer vehicles and trailers with LED bulbs but vehicles and trailers with incandescent bulbs will probably have this trouble with these newer Curt controllers. I tried to contact Curt to make them aware of this problem but I am in Canada and they wanted my state when filling out their enquiry form. No provision for a Canadian province. Hope this helps as this seem to be a big issue with a lot of people.