WOLFBOX WBH40 4A Hardwire Kit User Manual & Setup Guide
WOLFBOX WBH40 4A Hardwire Kit giving you grief? Lost the booklet? No stress.
You've got a G900 Pro or G900 TriPro on the windscreen and you want it watching the car while you're away from it. This is the WBH40 4A fuse-tap kit that makes that happen. Below is the wiring cheat sheet, the specs that matter, and fixes for the usual parking mode dramas, all checked against WOLFBOX's own manual, so you can get it sorted without guessing.
💡 Pro Tip: Test Before You Tap
Most parking mode problems come down to picking the wrong fuse. A cheap test light tells you in seconds which fuses stay live with the car off and which switch with the ignition.
Grab a Test Light here before you start.
Parking mode writes a lot of files. Pair it with a high-endurance card.
Quick Specs: Is This the Right Kit?
This kit is for the WOLFBOX G900 Pro and G900 TriPro only. Those two mirror cams draw more current than the rest of the range and need the 4A kit. If you run a G900, G850, G840S, G840H, G930, X3, X5 or i07, you want the standard WOLFBOX RP01 hardwire kit instead.
- Suits: WOLFBOX G900 Pro and G900 TriPro
- Rating: 4A, matched to the G900 Pro and TriPro
- Input: DC 12V to 24V vehicles
- Output: 5V, via a right-angle USB-C plug
- Working temperature: -30°C to 70°C (-22°F to 158°F)
- Low-voltage protection: fixed at 11.8V on 12V vehicles and 23.8V on 24V vehicles. There's no adjustment switch and no voltage display on this kit.
- Cable length: approx. 3.5m
- In the box: hardwire cable plus four types of fuse tap adapter, two sets (the manual lists ATO, MiniACN and Micro2)
Would rather not open the fuse box at all? The WBH40O OBD version plugs into the OBD-II port instead, and we've got a full WBH40O installer guide for it.
Which Wire Goes Where (Read This Twice)
Heads up if you've wired a VIOFO before: WOLFBOX uses the opposite colours. On this kit Yellow is constant power (B+) and Red is ACC (ignition). Get these backwards and parking mode will not behave.
| Wire | Connects To | WOLFBOX Fuse Guidance | What It Does |
|---|---|---|---|
| Yellow (B+) | Constant power fuse (live with the car off and on) | 7.5A to 25A fuse. Good picks: central locking, electric tailgate, trailer, fuel cap, interior lights, power seat adjust (not seat heating) | Keeps the camera powered while parked |
| Red (ACC) | Ignition fuse (live only with the car on) | 7.5A to 25A fuse. Good picks: anything marked ACC, centre console or screen, radio, cigarette lighter, USB ports | Tells the camera if you're driving or parked |
| Black (GND) | A metal bolt or screw near the fuse box | n/a | Earth. Never a plastic screw or panel. |
Fuses to leave alone: WOLFBOX says to avoid anything to do with the engine, transmission, ECU, steering, brakes, airbags/SRS, main lighting, sensors, control modules and air-con.
Two ACC gotchas: some cars have a delayed ACC circuit (the radio stays on until the doors are locked, for example), so parking mode only kicks in a few minutes after you lock up. And in some cars the cigarette lighter socket is always live. If yours is, pick a different ACC fuse.
Fitting the fuse taps: crimp the red and yellow wires onto the fuse tap adapters. The upper slot on the tap takes the dash cam fuse and the lower slot takes the original fuse you pulled out, and in an occupied slot it doesn't matter which way round the tap goes in. If you use an empty fuse slot instead, the tap's positive pin must go into the side that tests live.
Installation Steps
- Switch the car off. Fuses should only go in or come out with the car off.
- Find the fuse box. It's usually under the dash, on the left side of the driver's seat, in the boot or in the engine bay (your owner's manual shows where).
- Bolt the Black ground under a clean metal bolt or screw near the fuse box. If there isn't one close by, look a little further away.
- Find your B+ and ACC fuses, either from the fuse box diagram or with a test light on the 7.5A to 25A fuses. B+ lights up with the car off and on. ACC lights up only with the car on.
- With the car off again, fit the fuse taps to those two slots, then connect Yellow to B+ and Red to ACC.
- Route the cable up behind the A-pillar trim and along the headliner to the mirror, keeping clear of curtain airbags.
- Plug the USB-C into the camera's power port, not a camera input.
- Start the car and confirm the camera boots. Then enable parking mode in the camera menu, switch off, and check it changes over.
Low-Voltage Cut-Off (The Important Bit)
The kit watches your battery and cuts power to the camera when voltage drops too low, so the car still starts. On the WBH40 the cut-off is fixed: 11.8V on a 12V vehicle and 23.8V on a 24V vehicle. There's no switch to change it and no display on the box.
If the car sits for days at a time, or the battery is getting on, keep parked recording to shorter stretches and consider a dedicated battery pack.
Common Questions & Troubleshooting
The camera stays on and keeps recording normally after I switch off.
First check parking mode is switched on in the camera's settings. Then check the Red (ACC) wire. WOLFBOX says this happens when ACC has gone onto a constant fuse by mistake, or ACC isn't connected at all, so the camera thinks you're still driving. If your car has delayed ACC, give it a few minutes after locking before you decide it's not working.
The camera dies as soon as I turn the car off, with no parking mode.
The Yellow (B+) wire is on an ACC fuse, or the yellow and red wires are swapped. Move Yellow to a fuse your test light shows as live with the car off.
The camera won't power on at all.
WOLFBOX lists two causes: a bad ground (bolted to plastic or painted metal), or the Yellow wire sitting on a fuse slot with no power. Also check the USB-C is in the power port.
Parking mode still won't behave, and the wiring checks out.
WOLFBOX notes that some vehicles don't give a clean ACC signal change at ignition on and off, and in those cars parking functions may not work properly.
Can I use this kit on my X5 or G840S?
No. This 4A kit is for the G900 Pro and TriPro. The rest of the range takes the standard RP01 kit.
My battery still went flat.
The cut-off protects a healthy battery, not a tired one. Older batteries, short trips and long parks all add up. Get the battery tested, and consider a dash cam battery pack if the car sits for long stretches.
Do I need an auto electrician?
Not necessarily, but WOLFBOX itself recommends professional help if you're unsure. If you're not confident testing fuses and finding a good ground, get a professional installer to fit it. Wiring faults love pretending to be camera faults.
Official User Manual
Here is the full wiring diagram and instruction sheet straight from WOLFBOX.
Last reviewed: 17 September 2026. The wiring, cut-off values and fuse guidance described here follow WOLFBOX's official manual for the WBH40 hardwire kit. Product revisions change them, so if something on your kit does not match, check the label on the kit and the current manual linked on this page. If a specification, a feature or a price on this page is wrong or has gone out of date, tell us and we will correct it.