Controllers, Displays, Sensors & Wiring
Controller, display, sensor, and harness work covers the electronics between your battery and your motor — the controller, display unit, throttle, PAS/cadence and torque sensors, brake cut-offs, and every connector in between.
- Starting at
- $75
- Typical time
- 45 min–2.5 hr
- Warranty
- 90 days on labor
Sensor and connector work from $75. Controller/display replacement from $95 plus part.
This is the category that separates a mobile e-bike technician from a mobile bike mechanic. A cadence sensor needs about a 1–3mm gap to its magnet and puts out a clean 0–5V toggle; if the gap drifts or the magnet ring cracks, assist becomes intermittent and every symptom points at the battery. A torque sensor that's out of calibration throws codes that look like motor failure. A brake cut-off switch that sticks closed makes a perfectly healthy bike act dead.
Connectors are the other half. Higo, Julet, and generic waterproof bullets all corrode, and salt air accelerates it badly — a connector stored near the coast can show green, corroded pins long before the same part would inland. Intermittent power is very often a connector, and the fix is a clean, a crimp, and a dielectric reseal, not a new part.
I solder and crimp properly, heat-shrink every joint, and reseal to the original ingress rating. Harness repairs done with electrical tape and a twist come apart on the first wet ride.

Trip fee for this visit
- Zone 1 — San Clemente +FREE
- Zone 2 — Ladera Ranch +$35
- Zone 3 — Irvine +$65
Symptom → cause
What the bike is doing, and what it usually means
| What you notice | What it usually is |
|---|---|
| Assist comes and goes | Cadence sensor gap, cracked magnet ring, or a corroded connector |
| Display blank but bike still runs | Display unit or display cable |
| Speed reads zero or wildly wrong | Speed sensor alignment or spoke magnet |
| Assist cuts when you touch the brakes and stays off | Brake cut-off switch stuck closed |
| Throttle dead, pedal assist fine | Throttle unit or controller throttle input |
| Everything died after a rainy ride | Water ingress at a connector — usually fully repairable |
Prices
Electrical Repairs
Labor shown. Parts at cost plus 15%, quoted before I order anything.
| Charge port repair or replacement | $125–$195 |
|---|---|
| Battery mount contact service | $75 |
| BMS replacement+ part | $145 |
| Battery pack cell-level repairBench work — pickup and return included | from $225 |
| Battery replacement install+ pack; OEM or UL-certified only | $65 |
| Controller replacement+ part | $95 |
| Display replacement+ part | $75 |
| Throttle replacement+ part | $55 |
| PAS / cadence sensor + magnet ring+ part | $75 |
| Torque sensor service & calibration+ part if needed | $125 |
| Speed sensor + magnet alignment | $45 |
| Brake cut-off switch repair+ part | $55 |
| Connector rebuild (crimp, shrink, seal)Per connector, $95 for a full harness pass | $45 |
| Wiring harness repair | $95–$185 |
| Hub motor remove & reinstall | $145 |
| Mid-drive remove & reinstall | $185 |
| Geared hub motor rebuild+ gear set | from $185 |
| Hub motor replacement+ motor | $195 labor |
Free tools
Check it yourself first
Book service
Need controllers & wiring?
Takes a minute. You'll hear back within 30 minutes during business hours — and if it's faster to just call, call.
- Free quote before any work starts
- No trip fee in San Clemente, Dana Point or San Juan Cap
- 90 days on all labor
- Nothing gets added to the bill without a call first
FAQ
Before you book
Do you actually work on batteries, motors, and controllers — or just the mechanical stuff?
All of it. This is the main reason to call me instead of a general mobile bike mechanic. Most mobile bike services in Orange County explicitly decline battery, motor, throttle, and controller work, which means a bike with an electrical fault has nowhere local to go. I diagnose and repair charge ports, battery management systems, controllers, displays, throttles, cadence and torque sensors, brake cut-off switches, wiring harnesses, and hub and mid-drive motors — plus everything mechanical.
What brands do you work on?
Every brand. That includes direct-to-consumer bikes with no local dealer — Rad Power, Aventon, Lectric, Ride1Up, Velotric, Heybike, Himiway, Juiced, Super73, Segway — and dealer brands like Specialized Turbo, Trek, Giant, Cannondale, Electra, Gazelle, Tern, Pedego, Blix, Magnum, and Riese & Müller. On the motor side I work on Bosch, Shimano STEPS, Brose, Yamaha, Bafang, Fazua, Mahle, and generic hub systems. One honest caveat: Bosch and some Shimano systems lock firmware and certain diagnostics to authorized dealers. I can do every mechanical and electrical repair on those bikes and I'll tell you upfront on the rare occasion something has to go through a dealer.
My range dropped a lot. Do I need a new battery?
Probably not, and this is the most expensive assumption in e-bike ownership. Lost range has at least five common causes and only one of them is a worn battery: low tire pressure, a dragging brake rotor, a worn or dry chain, colder weather, corroded battery mount contacts, and actual capacity fade all produce the identical symptom. A $59 battery health test measures capacity against the pack's rated watt-hours and checks balance across cell groups, which tells you definitively which it is. That fee is waived if you have me do the repair. A new pack is $400 to $1,200 — it's worth $59 to find out whether you need one.
Is there a warranty on the work?
90 days on all labor. If something I worked on isn't right afterward, I come back and fix it — no trip fee, no argument, in any zone. Parts carry whatever warranty the manufacturer provides and I'll handle the claim paperwork with the brand for you.
What can't you do at my house?
Three things go to the bench rather than the driveway: cell-level battery pack repair (opening a lithium pack in a customer's garage isn't something a careful technician does), full wheel rebuilds and rim replacement, and internal motor rebuilds that need a press. For all three I pick the part or the bike up and bring it back, usually within two to four days. Everything else — including motor removal and reinstall, controller and display replacement, harness repair, brake bleeds, and full tune-ups — happens where your bike is.
Do you need power or water at my house?
No. The van carries its own power, lighting, compressed air, and water. All I need is a flat spot roughly the size of a parking space, within reason of where the bike is. Driveway, street, garage, courtyard, parking lot, or a turnout on a Laguna hillside all work fine.
Do I need to be home the whole time?
Only at the start and the end. I need five minutes with you at the beginning to understand what the bike is doing and to confirm the quote, and five minutes at the end to hand it back and show you what changed. In between you can go to work, take a call, or leave entirely.
My display is showing an error code. What does it mean?
It depends on the system, because every maker numbers its own faults: 21 is a speed sensor fault on a Bafang display but abnormal current on a Rad, and Shimano's codes start with W or E. The free error code lookup has the makers' own tables for Bafang, Bosch, Shimano STEPS, Rad Power Bikes, KT and Segway-Ninebot, with the maker's first step for each. If a code points at the battery or charger, stop charging and riding until it's checked.
Something not answered here? Just ask — I’d rather talk it through than have you guess.