Forum Discussion

ridesabout's avatar
ridesabout
Explorer
May 08, 2013

Voltage on trailer brake line with brakes not applied

I just purchased a new Chevy 3500 and when checking the voltage at the various prongs in the trailer plug at the rear of the truck discovered that there is a voltage reading of 3.5 to 4.6 on the trailer brake prong even though the brakes have not been applied. The Integrated Brake Controller readout shows no voltage output. Has anyone noticed this on their truck? Should there be such a reading? Any ideas?
Tow Vehicles
  • WyoTraveler's avatar
    WyoTraveler
    Explorer
    May 09, 2013
    Yes normal. Have someone apply brakes and voltage will go up. There is a votage to show when TT connected.
  • Learjet's avatar
    Learjet
    Explorer
    May 09, 2013
    voltage but no amps, put a load on it and it will go down I bet.
  • ScottG's avatar
    ScottG
    Nomad
    May 09, 2013
    It has to put out just a little voltage in order to sense the presence of the resistance in the magnets.
  • gijoecam's avatar
    gijoecam
    Explorer
    May 09, 2013
    ScottG wrote:
    It has to put out just a little voltage in order to sense the presence of the resistance in the magnets.


    This. The system is checking for a connection at all times to determine if there is a trailer connected or not. The voltage is usually always present with the key on, but is almost no current (a few milliamps at best, even if there was a dead short).

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