Troubleshooting Curt Wire Harness C53MJ On 2026 Acura MDX - No Turn Signals

Updated 12/11/2025 | Published 11/19/2025

Products Featured in This Question

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(18)

$75.30

Hook Probe Circuit Tester

(60)

$12.27

Question:

So, I have a 2026 Acura MDX tech package and installed the C53MJ trailer light part. I followed the directions and installed the 2 fuses as directed. I still do not have turn signals. Any thoughts. I tested my ground is good.

asked by: Don D

Expert Reply:

Hello Don, thanks for reaching out. Problems with these plug and play harnesses like the Curt # C53MJ are not common, but there are a few things we can check. First make sure the fuses are fully inserted and seated. Also make sure the plug that goes to the factory harness is plugged in all the way. If all of that checks out, the next step will be to test the converter module using a wire probe like part # PTW2993. Check the input wires going from the factory harness to the module and see if all signals are normal. They check the output wires on the 4-flat side and compare your findings. If the turn signal wire tests normal going into the module, but the output isn't there, this means the module is bad and needs to be replaced.

expert reply by: Jesse M

Jesse M.

12/8/2025

Hey Don, how did things go after you checked the fuses and tested the converter module on your MDX wiring harness? Knowing what you found with the probe test could help others troubleshoot similar signal issues.

Don D.

12/11/2025

@JesseM I did not test the converter module, but I did put the fuse in the small trailer position in the fuse box like an earlier post had mentioned. Turn signals, brake lights and parking lights work correctly now. Perhaps a review of the MDX wiring system is needed and update the instructions.