Controller replacement runs $120 to $350 in our network's typical range. But the most important number on this page might be the smaller one next to it in the table below: diagnostic work on error codes runs $60 to $300, and cutout diagnosis runs $75 to $350. That ordering is deliberate. Dead-bike symptoms are more often a fuse or a connector than a dead controller, so the cheapest controller replacement is the one you confirm you do not need.
What drives the price
Diagnosis time comes first. The controller is the bike's brain, and its failure symptoms, a totally dead bike with a good battery, assist that surges then quits, a burning smell, overlap with cheaper faults like a blown fuse, a corroded connector, or a brake sensor stuck engaged. A careful diagnosis sorts that out before money is spent.
The part comes second, and matching it is the job. Controllers must match your bike's voltage and plug standard, so this is never a grab-the-generic-box purchase. Brand matters a lot here. Controller faults are the signature Rad failure, especially on 2019 to 2022 RadRunner and RadRover builds, and the flip side of a common failure is a solved one: replacement controllers are plentiful, the swap is routine, and our network's Rad range is $140 to $260. At the other extreme, generic imports often carry unlabeled controllers, and the honest first conversation is repair cost versus bike value, before any parts are ordered.
Where the money goes
The bill splits into diagnostic labor, the controller itself, and the swap: transferring connectors, securing the harness, and verifying every system afterward. Where water intrusion caused the failure, waterproofing the connections is part of doing the job right, or the new controller inherits the old one's fate.
DIY or call a tech
The genuine DIY path here is confirmation, not repair. Do a full power cycle: turn the bike off, remove the battery for one minute, reinstall it. Check for a small fuse near the battery mount or on the battery itself. Confirm the battery is actually good, meaning the charger indicator behaves normally and the pack is seated firmly. Inspect the visible connectors for corrosion or damage. If the display shows an error code, note the exact code and your bike's brand and model, since codes are brand-specific and the code usually tells us what parts to bring.
If the bike smells burnt, stop there. There is no DIY fix for a blown controller, and the value you can add is ruling out the cheap causes so nobody buys a controller the bike did not need.
When replacement beats repair
For controllers, replacement essentially is the repair: field-level fixes for blown internals do not exist, so once diagnosis lands on the controller, the questions become which unit and whether the bike is worth it. On a mainstream brand with plentiful parts, the answer is usually straightforward. On an orphaned or unlabeled system, the part hunt is the cost, and that is where the repair-versus-value conversation belongs. One more honest note: overloading from aftermarket modifications is on the known-cause list for controller failure, so our recommendation is to weigh that before de-restricting a bike you depend on.
Mobile repair suits this fault well: the tech diagnoses at your driveway, specs the right unit for your voltage and plug standard, and gives you a written estimate before any repair work begins, so the decision is yours with real numbers in hand.