Primus IQ Brake Controller Setup Help

Discussion in 'Etrailer.com Trailers and Towing Forum' started by Maycat, Jul 15, 2018.

  1. Maycat

    Maycat Member

    37
    12
    Jan 28, 2018
    Chico, California
    Hello,

    We have a Primus IQ Brake Controller that we took on one trip and were unable to get set up. We got our van's brakes super hot and they smoked for over 30 minutes after coming down 5 summits. We are now getting ready for another trip with the trailer in 5 days and we are trying to get it calibrated.

    Now "SH" is coming up occasionally, so we are about to start searching for the short in the system. Also, every time we try to calibrate the trailer brake, it will go from 0.0 to 13. The instructions show we need to dial the power to 6.0 to get started while pushing in the manual slide knob. I figured out that 13 is the voltage, and that's not right. A friend is on their way with a circuit tester so we will see if we can find a short or wiring issue. If that is not it, any ideas? We leave in 5 days and will be driving down a very steep road in the mountains then.
     
  2. Raycfe

    Raycfe Waterford Ct.

    13,190
    630
    Oct 3, 2007
    Waterford, Ct
    You have a wiring problem. The blue wire have a bad connection or a bare spot that is going to ground. Also check the ground connections. If the blue wire is shorted you could cook your brake controller.
     
  3. Maycat

    Maycat Member

    37
    12
    Jan 28, 2018
    Chico, California
    We took the trailer to a friend's today who is an auto mechanic to have him check it out. When we hooked it up it was no longer showing a short, but was showing not connected. He cleaned the connectors and I wiggled the 7 pin adapter and pushed it back in and briefly it was was showing connected. We ordered a 6 pin square to 6 round cable and he is going to mod it.

    He wants us to try replacing the 6 pin cord first and then go from there.
     
  4. Rusty2192

    Rusty2192 Active Member

    616
    166
    Jul 30, 2014
    Kentucky
    When driving down long steep slopes, be sure to downshift to have the engine help hold you back. Otherwise you’ll overheat your brakes which could lead to failure, even with roperly working trailer brakes.
     
  5. Mofonator

    Mofonator New Member

    7
    0
    Jul 9, 2018
    I understand the gear down concept, but how much do you gear down? My Sienna has an 8 speed transmission. On a highway at 100 km/h Would you go to 6th or 5th?
     
  6. Rusty2192

    Rusty2192 Active Member

    616
    166
    Jul 30, 2014
    Kentucky
    According to your owners manual, you shouldn’t be above 6th anytime while towing anyway. Similarly, my 2016 Sienna with a 6 speed tells me to limit it to 4th.

    As for how low to go, you go as low as needed to maintain speed. As long as the engine isn’t red lining, it’s fine to let it rev up. At that speed, I doubt you’ll need to downshift too much unless it’s a really steep hill. Just go down a gear and if you are still speeding up, go down one more. Rinse and repeat until you find the sweet spot.
     
  7. Mofonator

    Mofonator New Member

    7
    0
    Jul 9, 2018

    Sigh. nothing like an RTFM response to make you feel dense.:) Thanks Rusty!
     

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