Below is a listing of commonly asked questions and answers for the Primus® IQ, Proportional Brake Controller for Trailers with 1-3 Axles, Gray. If you can't find the
information you need here, please submit your question to us using the form in our contact page.
Select a question to view the answer.
The display shows one dot or the display shows two dots.
The left dot is the power indicator; meaning that the control is powered and ready. The right dot is the boost indicator. This tells you that some level of boost is set.
Will the Prodigy or Primus IQ work with electric over hydraulic brakes?
These controls were designed to operate electric brakes that are activated by electro- magnets. They have not been tested for the use on electric over hydraulic brakes. Please contact the manufacturer of the hydraulic control unit for their recommendation.
Display only goes up to 0.0 to 4.2 when applying brakes.
With Proportional Type digital controls the vehicle must be in motion for the control to have output. If the vehicle is sitting still with the vehicle's brake depressed or stopping very slowly the voltage displayed will be very low on the control. The is normal operation.
Display shows "PL"
The control detected a power loss on the Black wire during a braking event.
Possible causes:
- Applied brake pedal or manual lever while connecting the control to power.
- Poor connection on black wire, Fuse or Circuit Breaker.
- Fault circuit breaker or Fuse.
The display shows "og" or "OG"
The control detects an open ground.
Possible causes:
- Poor or no connection to ground on the White wire of the control.
The display is blank.
These controls will go into a Sleep Mode after approximately 15 minutes of detecting no movement or input.
Possible causes:
- Control is in sleep mode.
- No power on Black wire of control.
- Poor or no connection to ground on white wire of control.
The top or bottom horizontal bars are flashing.
If the top bars are flashing, this tells you that the control is mounted at too steep of an angle. If the bottom bars are flashing, this tells you that the control is mounted at too low of an angle.
No "C" with trailer connected or shows "nc" with trailer connected.
These controls have to have a complete circuit on the Blue wire to the brake magnets and then to ground, with the proper resistance and an inductive load.
Possible causes:
- Open on electric brake wire (Blue wire) of brake circuit.
- Open on ground wire of brake circuit.
- Power back feed on Blue wire.
- Trailer has electric over hydraulic brakes.
Display shows "SH"
The control detects a short to ground on the electric brake wire (Blue wire).
Possible causes:
- Short to ground on electric brake wire (Blue wire).
- Trailer has electric over hydraulic brakes.
Display shows "OL"
The control detects excessive current on the electric brake wire (Blue wire).
Possible causes:
- Short to ground on brake wire (Blue wire).
- Trailer has electric over hydraulic brakes.
Will the Primus IQ work with electric over hydraulic brakes?
The Primus IQ was designed to operate electric brakes that are activated by electro-magnets. They have not been tested for the use on electric over hydraulic brakes. Please contact the manufacturer of the hydraulic control unit for their recommendations.