Troubleshooting Primus IQ Brake Controller that Shows N.C. on Display
Updated 07/30/2021 | Published 09/02/2016
Question:
With my truck running and trailer hooked up. I am getting the . . Code on the controller, my trailer lights all work but the brakes wont. Also when manually depressing the controller it gives me the n.c. code, what do I need to do!!!
asked by: Dale S
Expert Reply:
There are 4 possible reasons why the Tekonsha Primus, # TK90160, is telling you N.C.
1. Trailer not connected to tow vehicle.
2. Trailer connected with open circuit on brake line.
3. Trailer connector disconnected or corroded.
4. Loss of trailer brake magnet ground.
The first one is easy enough to solve so we will go on to the second possible issue. An open circuit on the brake line or a short to the brake circuit could be caused by a couple of different issues. First, it is possible that there is corrosion or dirt in the trailer connector (see number 3 above) and that is causing a short from the 12 volt circuit to the brake circuit.
Corrosion can also build up behind the connectors where the wires attach where you cannot see it so be sure to check that as well. Check both the vehicle side and trailer side connectors.
If the brake controller checks out then you could have a problem with the trailer brake magnets. To test the brake magnets you can start with a visual inspection. If you can see the windings coming through then the magnets will need to be replaced. To further test the magnets I have included a link to an FAQ article that will help.
Chad B.
6/17/2020
I installed this brake controller on my truck and when I hooked my camper up it said the slide control did nothing. It then said PL . I disconnected the plug, and plugged it back in. I set to the settings that the manual said to set it at, and still nothing. After driving it went back to PL. While driving, the numbers on the brake control were bouncing all over the place. It even does it without my camper hooked up to it.
Chris R.
6/22/2020
Jamie M.
8/10/2020
I installed this on my truck using the adapter harness. Everything checks out on the controller. It shows n.c. when it's not connected then goes to . . When it's hooked up to my trailer, it shows .c. and when I press the brake pedal, it shows the increase proportional voltage. However, when tuning the unit with my trailer, I found that I am getting to braking from the trailer at all. This is a 5-year old trailer, so I'd be surprised if it was the brake magents. Is there a manual way to make the brake controller output a corresponding voltage so I can probe the truck 7-way connector?
Product Page this Question was Asked From
Tekonsha Primus IQ Trailer Brake Controller - Up to 3 Axles - Proportional
- Trailer Brake Controller
- Proportional Controller
- Electric
- Splice-In
- Under-Dash Box
- Under-Dash
- Up to 3 Axles
- LED Display
- Single Trailer Only
- Tekonsha
more information >
Featured Help Information
Instructions
Miscellaneous Media
Continue Researching
- Search Results: brake controller
- Search Results: dexter oil cap
- Search Results: etbc7 wiring kit
- Search Results: etb7
- Shop: Trailer Hub and Drum Assembly - 5,200-lb and 6,000-lb Axles - 12" - 6 on 5-1/2 - Pre-Greased
- Search Results: id bar trailer lights
- Shop: Brake Controller
- Shop: Demco DA86 Brake Actuator for Disc Brakes w/ Solenoid - Zinc Plated - 2" Ball - 8,600 lbs
- Search Results: torsion axle
- Search Results: torsion axel for trailer
- Shop: Easy Grease Trailer Hub and Drum Assembly for 5.2K & 6K Axles - 12" - 6 on 5-1/2 - Pre-Greased
- Shop: etrailer Electric Trailer Brakes - Self-Adjusting - 12" - Left/Right Hand - 5.2K to 7K
- Q&A: What Light Will Replace My Light with DOT 16P2ST2 T35 16 Stamped on it for My Truck?
- Shop: TecNiq Stop Tail Turn Light - 6" - Oval - Tripole - Grommet Mount
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Video: Install: 7-Way RV Upgrade Kit for Trailer Brake Controller Installation on a 2023 Toyota Highlander
- Shop: Redarc Tow-Pro Liberty Brake Controller w/ Universal Wiring Harness - Dash Knob - Proportional
- Shop: 7-Way RV Upgrade Kit for Trailer Brake Controller Installation - 12 Gauge Wires
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Shop: Trailer Wiring
- Video: Tekonsha OEM Replacement Vehicle Wiring Harness w Brake Controller Adapter Review
- Video: Installing the Redarc Tow-Pro Liberty Brake Controller on a 2017 Toyota Highlander
- Video: Comprehensive Review: Redarc Tow-Pro Liberty Brake Controller w/ Universal Wiring Harness
- Video: Easy Grease Trailer Hub and Drum Assembly for 5.2K & 6K Axles: The Breakdown
- Video: etrailer VS Dexter Self Adjusting Brakes Comparison
- Q&A: Installing The Roadmaster Invisbrake On A 2021 Ford Escape Hybrid
- Video: Checking Out the Trailer Hub and Drum Assembly
- Q&A: Older Generation Primus Cequent Brake Controller User Manual
- Shop: Suspension Enhancement
- Q&A: Troubleshooting Tekonsha Primus IQ Trailer Brake Controller That Shows Connected But Doesnt Work
on Trailer Brake Controller
Bill I.
3/24/2020
After installing and using on one of my multiple trailers, everything worked fine with the brake controller, hooked up to one of my other trailers originally showed ‘c’ and showed voltage amount, then went to ‘nc’.Checked all connections redid all wire connections under the trailer with no avail, removed trailer plug , finally pulled the break away to test and see if there was a wiring issue or magnet problem of which trailer wheels locked up and could not even move the trailer in either direction still showing ‘nc’Only seems to be this trailer, where do I start testing