A proportional controller varies output in response to measured deceleration. A time-delay controller builds output using the selected rate and ceiling while the brake signal remains active. Gain, boost, setup and brake condition affect the result; proportional does not mean a perfect copy of pedal force.
Control method and installation style are different choices. A dash box, hidden module or 7-way plug-in controller can all use proportional control. The mounting format is not a third braking method.
Compatibility is a separate check too. Within Tekonsha’s range, the time-delay unit below covers more axles than the mid-priced proportional one, and works with brake types the proportional one is documented as untested for.
The two-way answer, first
| What it handles | Time-delay | Proportional |
|---|---|---|
| How it decides braking effort | A selected ramp and ceiling while the brake signal is on | Responds to measured deceleration within the selected settings |
| Knows how hard you are braking | No | Yes |
| Uses an inertial sensor for braking effort | No | Yes |
| Mounting orientation matters | No — mounts in any position | On traditional units yes; on three-axis units no |
| Needs levelling after fitting | No | No — modern units self-level |
| Behaviour in a gentle stop | Can ask for more braking than the stop needs | Lower output, subject to settings |
| Behaviour in an emergency stop | Ramps at its fixed rate regardless | Output responds to deceleration within the gain limit |
| Settings need checking when load or conditions change | Yes | Yes |
| Cost | Lowest in the category | Mid to high |
| Suits | Light, occasional, flat-country towing | Heavy trailers, hills, frequent towing |
How each one actually works
Read each column from top to bottom. Both examples keep the controller settings and brake-signal duration unchanged. Heights show relative levels within each row, not shared physical units.
Gentle braking
The proportional trace stays lower. The fixed ramp can build beyond the effort wanted for this gentle stop.
Firmer braking
The proportional trace rises further. The fixed ramp still uses its selected rate and ceiling.
Shapes explain the control methods, not stopping performance. Gain limits output; time-delay sync changes the ramp. Proportional boost can add initial output and change sensitivity. Calibration, brake condition and electrical or hydraulic response affect the result. The small offsets drawn here do not measure a delay, and proportional output is not a perfect copy of pedal force. Stationary hold, manual override and boost are omitted.
Sources: Tekonsha Brakeman IV and P3 manual, pp. 1 and 5–6. Use the exact model’s setup procedure.
Time-delay uses the brake signal and a selected ramp. Tekonsha describes the Brakeman IV as increasing output at a fixed rate, with power and sync controls. Holding the same settings and signal duration produces the same intended ramp; a short brake application can end before it reaches the ceiling.
Proportional uses deceleration. An inertial sensor measures the tow vehicle slowing. Output varies with that input and the selected gain and boost. The P3 manual documents both boost onset and stationary hold, so neither zero output at rest nor exact instantaneous matching is a universal rule.
The third architecture, which no ranking guide covers
Every page currently answering this question describes a dashboard box. The newest thing in the category is not a box at all.
CURT’s Echo plugs into the tow vehicle’s 7-way socket, senses with a triple-axis accelerometer, and uses your phone as the display and the controls. It is proportional in behaviour and shares nothing else with a traditional proportional controller: no dash real estate, no vehicle-specific harness, and it moves between vehicles in seconds.
There is a related move on the dash-mounted side. REDARC’s Tow-Pro Elite is also a three-axis design, which is what lets its module hide behind the dash in any orientation with only a knob showing — the orientation constraint that older guides treat as inherent to proportional controllers has been engineered out. That pairing is covered in Tekonsha P3 vs REDARC Tow-Pro Elite.
So “proportional” no longer describes one kind of hardware. It describes a behaviour, delivered three ways.
Three controllers, three architectures
| Model | Sensing | Where it mounts | Axles | Price | Buy |
|---|---|---|---|---|---|
| Tekonsha Prodigy P3 | Inertial sensor — axis count not published | Dash box, any vertical angle, must face the direction of travel | 1–4 axles | $$ | Check price(opens in a new tab) |
| Tekonsha Brakeman IV | None — a fixed time ramp, not a measurement | Anywhere within the driver's reach, any orientation | 1–4 axles | $ | Check price(opens in a new tab) |
| CURT Echo | Triple-axis accelerometer | Plugs into the 7-way socket — no dash unit at all | 1–2 axles | $$$ | Check price(opens in a new tab) |
Two of these three are made by the same company, which is deliberate — it lets the control type be compared without brand quality confusing the picture.
What the older guides get backwards
Two claims recur across the pages ranking for this query, and both are contradicted by the manufacturers’ own documentation.
“Proportional controllers have to be levelled.” They do not, and have not for a long time. Tekonsha’s P3 manual: “The P3 will automatically acquire the proper level setting. It will also automatically adjust as you travel up or down hills.” The real constraint on a traditional proportional unit is orientation — the P3 can sit at any vertical angle but must face the direction of travel. That is a different thing from levelling, and three-axis units do not have it at all.
“Time-delay is the compromise option, so it does less.” On the axis that matters — braking behaviour — yes. On fitment, the opposite is true, and it is demonstrable inside one manufacturer’s catalogue:
| Brakeman IV (time-delay) | Primus IQ (proportional) | |
|---|---|---|
| Axles | 1–4 | 1–3 |
| Electric over hydraulic | Yes | “Have not been tested for the use on electric over hydraulic brakes” |
| Mounting | Any orientation | Self-levels only within a 90-degree vertical range |
| Price | Lowest here | Higher |
Both are Tekonsha. The cheaper unit fits more trailers and more brake systems than the dearer one. That is not an argument for buying the time-delay controller — the braking behaviour is still the main event — but it is an argument for checking the model rather than trusting the category, and for ignoring anyone who tells you the control type settles compatibility.
Where the two types are identical
- Both need the model’s setup procedure. The P3 manual-control test and Echo brake-pedal test are different. Use the brake-gain worksheet with the exact manual, including any warm-up instructions.
- Both need settings checked for the load and conditions. Proportional sensing does not eliminate gain adjustment.
- Neither repairs worn or badly adjusted brakes. Diagnose the brake system before treating a controller upgrade as the fix.
- Both need a reachable manual control. Confirm its operation and the model’s mounting and calibration requirements before towing.
Which one, for what you tow
Proportional, if you tow a travel trailer or fifth wheel with any regularity, tow in hills, or the trailer is a significant fraction of the tow vehicle’s weight. This is most RV owners, and it is the honest recommendation despite costing more.
Time-delay, if the trailer is light, the towing is occasional and flat, or the budget is genuinely tight — and be aware you are choosing one compromise setting rather than buying a worse-built product. Also worth a look if there is nowhere in the cab that faces forward, though a three-axis proportional unit now solves that too.
The 7-way plug-in type, if you move one trailer between several vehicles, or you refuse to drill a dash. Only for one- and two-axle trailers, and only if you are comfortable that the interface is an app.
Once you have settled the control type, the five controllers we hold records for are set out side by side — with the axle and brake-type ratings that decide which ones are candidates at all.
Proportional, for regular or heavy towing
Tekonsha Prodigy P3
Brakes in proportion to how hard you are actually stopping. Four axles, electric-over-hydraulic on a menu setting, lifetime warranty.
Time-delay, and not a downgrade on paper
Tekonsha Brakeman IV
Same maker, same four axles, same 30 A, also does electric-over-hydraulic — and mounts anywhere, because there is no sensor to orient.
The third architecture nobody's guide covers
CURT Echo
Proportional sensing in the 7-way socket instead of the dash, with your phone as the display. Two axles only, and the app has to stay in the foreground.
Questions worth answering
What is the difference between a proportional and a time-delay brake controller?
Proportional output responds to measured deceleration within the selected gain and boost settings. Time-delay output follows its selected ramp and ceiling while the brake signal is active. With the same settings and signal duration, the timed ramp does not adapt to a gentle versus firm stop by measuring deceleration. Neither method removes setup requirements.
Are time-delay brake controllers any good?
Tekonsha describes the Brakeman IV as suited to basic, light-duty towing. The tradeoff is its fixed ramp: a setting suitable for one stop can deliver too much or too little output for another. Check the exact controller's ratings and follow its setup procedure; price and control method alone do not establish suitability for a trailer.
Is a proportional controller worth the extra money?
For most RV buyers, yes — but for the reason above rather than the reasons usually given. It is not that proportional controllers are better made, support more trailers or fit more vehicles; within Tekonsha's own range the cheaper time-delay Brakeman IV covers more axles than the dearer proportional Primus IQ and works with brake types the Primus IQ is documented as untested for. What you are buying is braking effort that tracks the stop you are actually making.
Which type mounts anywhere?
Time-delay, and it is a structural consequence rather than a feature someone chose. With no inertial sensor there is nothing that has to know which way is forward. Draw-Tite states it of the class — timed controllers "can be mounted in any position - horizontal, vertical, even turned upside down" — and Tekonsha says of the Brakeman IV that "there's no requirement that it be positioned in the direction of travel". Traditional proportional controllers do have an orientation constraint. Newer three-axis proportional units have removed it, which is the point of the third architecture below.
Do proportional brake controllers need to be levelled?
No, and this is the most persistent error in the older guides. Tekonsha's Prodigy P3 manual states "The P3 will automatically acquire the proper level setting. It will also automatically adjust as you travel up or down hills." Levelling is not an installation step. What a traditional proportional controller does need is to face the direction of travel — an orientation requirement, not a levelling one.
What is a wireless or Bluetooth brake controller?
A third architecture that the standard proportional-versus-time-delay framing does not describe. CURT's Echo plugs into the tow vehicle's 7-way socket, senses with a triple-axis accelerometer, and uses your phone as the display and control panel. It is proportional in behaviour but shares none of the dash-mounted installation. The trade-offs are real: two axles maximum, and CURT's manual warns the app "must be operating in the foreground" because running it in the background "may cause delays in braking response when using the manual override button".
Does a time-delay controller work with electric-over-hydraulic brakes?
Sometimes, and the answer does not follow from the control type — which is the thing worth knowing. Tekonsha's time-delay Brakeman IV "works with electric or electric over hydraulic braking systems". Its proportional Primus IQ is documented by Tekonsha as designed for electric brakes and states these controllers "have not been tested for the use on electric over hydraulic brakes". Same manufacturer, opposite answers, and the cheaper unit is the compatible one. Check the specific model.
How do you set the gain on each type?
Follow the exact model's procedure with the trailer loaded for travel. The P3's manual-control test and the Echo's brake-pedal test are different; do not combine them into one generic procedure. The linked brake-gain worksheet separates those instructions. Recheck settings as directed when the load or conditions change.
Can I tell which type I have?
Find the model number and check its manual. Display output alone does not identify the control method: proportional units can have initial boost and stationary hold, and both types can have manual override. The P3, for example, can maintain output at a standstill with the pedal applied. Do not watch a controller display while driving to identify it.