Troubleshooting Trailer Disconnected Alarm on 2018 Toyota Tundra with 2010 Airstream Trailer  

Question:

Expert Reply:

A trailer disconnected alarm has to do with the trailer brake controller pin draw on the 5 o'clock pin position on most vehicles. If you have a trailer connected and the alarm is on, you most likely don't have enough draw on that pin for the vehicle to recognize connection. Normally this is due to corrosion at the connection, but on a new truck, that most likely isn't the issue. You may want to clean the connections with sandpaper and use dielectric grease # 11755 to confirm a clean connection.

To test your pin connection and brakes working, you can use the brake controller manual override with the trailer connected and slowly increase the voltage to that pin. If the error alarm goes off then you know that voltage is the issue.

Toyota has had issues with this and there are many with the same issues. Truck by itself works fine, trailer checked out as fine, yet error when used together. Most people have moved to aftermarket brake controller like the Tekonsha Prodigy RF Wireless Trailer Brake Controller # TK94FR and that solves the issue because it doesn't utilize that brake controller output pin. Similarly you can the Curt Echo Wireless # C51180 which also does not utilize that pin.

The load resistor # DI34ZR you referenced will draw more power on the brake output wire when used on the trailer side of the connection, so that may solve the issue, but I can't confirm that fix as we haven't tested it with that error alarm yet.

expert reply by: Jason S

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