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How-to guide

RadRunner dead controller or display: aftermarket replacement options

Replacement paths for a failed controller or display on the RadRunner 1, 2 and Plus: Rad's own parts first, Rad's LCD display upgrade, an Area 13 harness, and what's outside this guide.

Last edited Nov 8, 2026 by Pedalwise team Edit History Add a subpage

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Difficulty
Moderate
Time
1 to 2 hours

Tools

This guide is for a RadRunner 1, RadRunner 2 or RadRunner Plus whose controller or display has died, and it sorts the replacement options from Rad's own parts to aftermarket pieces. Diagnose first, because a loose plug or a damaged harness can look exactly like a dead controller or screen. Work through RadRunner error 30, RadRunner error 24 and Rad Power Bikes troubleshooting before you buy anything.

Turn the bike off and remove the battery before you unplug anything. Never open the controller, display, motor or battery, and never cut or splice the wiring. If you aren't sure which part failed, find a shop.

When this makes sense

Start with Rad's own parts. Rad's RadRunner controller replacement guide covers the Runner 1, Runner 2 and Runner 1 Plus, and says to swap the controller only after Rad Product Support has found it damaged or not working, using a replacement controller from Rad. The Runner 3 Plus has its own procedure. Rad's LED display replacement guide says the same for the stock LED display on the RadRunner, RadMission and RadExpand.

When we read Rad's online parts store for the RadRunner 2 and the RadRunner Plus on Nov 9, 2026, it listed brake levers and cables but no controllers or displays, so ask Rad Product Support for those.

Riders look at aftermarket parts when Rad can't supply the part, the wait is long, or the bike is out of warranty.

Options

Rad's own controller (moderate, plug and play)

  • What it replaces: the controller, which sits under the skid plate.
  • What must match: the controller for your exact model, supplied by Rad after Product Support confirms the fault.
  • What's involved: Rad's guide has you take off the cable cover and skid plate, unplug each connector by pulling it straight apart, plug in the new controller, route the harness, PAS sensor and motor cables, then refit the skid plate bolts to 5 Nm, as Rad states.

Rad's LED display or LCD display upgrade (easy, plug and play)

  • What it replaces: the handlebar display. Rad sells an LCD Display Upgrade that replaces the stock LED display on the RadRunner, RadMission and RadExpand. Rad's LCD upgrade installation guide names the RadRunner 1 and 2. For a RadRunner Plus, ask Rad which display fits.
  • What must match: it plugs into the same display connector. Rad lists a speedometer, odometer, trip, average and top speed, and assist levels 1 to 4. No price showed on the product page when we read it.
  • What's involved: unscrew the connector's metal collar, pull the halves straight apart, clamp the LCD on the crossbar and its remote on the left grip, then plug in by lining up the notch and pins and pushing straight together.

Area 13 E-Bikes Rad wiring harness (easy to moderate)

If the fault is the harness between the handlebar and the controller rather than the controller, Area 13 E-Bikes sells a Rad Wiring Harness, listed at $40 and in stock (read Nov 9, 2026). Area 13 says it fits Rad bikes from about 2017 to 2022 but not the RadRover 6 or RadCity 5, that it is a little longer than stock, and that it is an aftermarket part not affiliated with Rad. Ask Area 13 to confirm it fits your RadRunner before you order.

Area 13 controller and display kit (moderate)

If both the controller and display have failed, Area 13 E-Bikes sells an aftermarket Rad kit that replaces both together with its own 35A controller and LCD8H display, listed at $229 and shown as out of stock (read Nov 9, 2026). The LCD8H display works only with Area 13's own controller, not the stock one. It is not a Rad part and Area 13 sells it as a higher power kit, so ask Area 13 about fit, set the speed limit to your bike's original class, and read the class note below.

A universal controller and display (not covered)

We didn't find a seller's page showing a universal KT style controller and display that fits the RadRunner at stock power, so we don't cover one here. For how controllers and displays are matched in general, see E-bike controller and E-bike display.

Setting it up

  • Rad's own parts are made for the bike, so after the swap check that the display powers on, assist levels change, the throttle works and the brake levers cut the motor. See Check brake cutoff and throttle.
  • On the LCD, set your units and pick the assist level you like. Rad's LCD Display Features video below shows the menus.
  • Leave the speed limit at the class your bike was sold as. Class 1 and 2 bikes stop motor help at 20 mph and Class 3 at 28 mph with pedal assist (Bosch, three class system). Makers put a class sticker on the frame.
  • Going past your e-bike class limits can make the bike illegal on public roads and bike paths in many places, voids the warranty, and adds wear on the battery, motor and brakes. A bike set up as Class 3 needs a Class 3 label.

Videos

LCD Display Features | Rad Tech from Rad Power Bikes: a tour of the LCD display's functions and buttons.
RadMission LCD Display Upgrade Installation, How To from Goose House Daily: an owner swaps the LED display for Rad's LCD upgrade, the same swap Rad lists for the RadRunner.
Rad Power Bikes Electrical Issues (Solved) from Robinson Cycle: a shop tracks down an electrical fault on a Rad bike.

When to get a pro

Get a shop or Rad Product Support involved if error 30 or a blank display comes back after a careful connector check, if any pin is bent or burnt, or if you're not sure the controller is the fault. A tech can run the no power diagnosis. Anything inside the battery, motor or controller is shop work.

Sources

Stuck after these checks? Find a shop near you.

Need a pro?

If these steps didn't fix it, find a shop near you in our partner network. For battery or wiring trouble, look for shops marked Battery and electrical.

Talk

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