A proportional brake controller varies trailer braking with the tow vehicle's deceleration, while a time-delay controller builds braking output on a set ramp after you press the pedal. Choose by braking behavior, setup needs, controller mounting and compatibility with your trailer's brake system. Check the tow vehicle manual, controller instructions and local trailer-brake rules before installation.
The controller must match the trailer’s brakes and the tow vehicle’s wiring before its braking behavior matters.
Compare controller types
| Type | How it applies trailer brakes | What to check | Suits |
|---|---|---|---|
| Proportional | Varies output with the tow vehicle’s deceleration | Sensor orientation, mounting and compatibility with the brake system | Drivers who want trailer output to follow how firmly the tow vehicle slows |
| Time-delay | Ramps output at a set rate after the brake pedal is applied | Ramp adjustment, initial output and mounting | Drivers who prefer a preset ramp they can adjust for their trailer |
Tekonsha describes proportional controllers as applying trailer brakes at the same time and intensity as the tow vehicle, while its time-delay controllers build output at a predetermined rate. Individual models can have different adjustment controls and compatibility limits.
Match the trailer brake system
Check whether the trailer uses electric drum brakes, electric-over-hydraulic brakes or another system. Controller compatibility varies by model. For example, Tekonsha’s Primus IQ product page says that model is designed for electric brakes activated by electromagnets and directs users with electric-over-hydraulic brakes to contact the hydraulic-unit maker.
Compare the controller’s supported axle or wheel count with the trailer, then check the controller instructions for the required tow-vehicle connection. Some setups use a vehicle-specific harness; others need a different wiring method. Do not assume two controllers with the same plug have the same brake-system compatibility.
Set up and adjust the controller
Install and orient the controller as its manual specifies. Follow its setup procedure to set initial output and, where available, ramp or boost behavior. Test the trailer brakes in a safe area and adjust them according to the manufacturer instructions before towing in traffic.
Trailer brake laws depend on where you travel. Check the applicable state or provincial rules and your vehicle manual. For the rest of the towing limits, see trailer hitch classes and tongue weight. Before storing the rig through freezing weather, use the RV winterizing checklist.
Sources
- Tekonsha proportional controllers
- Tekonsha time-delay controllers
- Tekonsha Primus IQ product specifications and compatibility FAQ
Related: all towing gear.
Common questions
What does a proportional brake controller do?
It senses how the tow vehicle is slowing and applies trailer-brake output in step with that deceleration.
How does a time-delay brake controller work?
It ramps trailer-brake output at a preset rate after the tow vehicle's brake pedal is applied.
Are proportional brake controllers better?
They match output to deceleration, while time-delay models use a set ramp that the driver adjusts. The right choice depends on trailer-brake compatibility, setup and driving needs.
How do I choose a trailer brake controller?
Match the controller to the trailer's brake type and axle count, then check tow-vehicle wiring, mounting and the controller maker's compatibility list.