Dash Cam Hardwire Kit Not Working or Blowing Fuses? How to Fix It
Charles Alexis
A hardwire kit is the cleanest way to power a dash cam. It is also where most install problems come from.
Before you start
You are working on the car’s fuse box. If you are not comfortable with a multimeter and fuse taps, get an auto electrician to do it. A bad install can cause electrical faults that cost far more than the camera.
Symptom: camera does not power on at all
Check these in order:
- The earth. The earth wire must be on bare metal. A bolt on a painted panel or plastic trim will not work. This is the most common mistake.
- The fuse tap direction. Fuse taps (add-a-fuse) only work properly one way round. If the tap is fitted backwards, the circuit may still work but the camera gets no power, or the tap’s own fuse takes the full load.
- The fuses in the tap. Most taps hold two fuses: the original circuit fuse and a small one for the camera. Check both.
- The fuse you chose. Some fuses are dead in certain states, or are not used on that vehicle. Test with a multimeter before you tap into it.
- The connector at the camera. Make sure the kit’s plug is fully seated.
Symptom: camera works with the ignition on, but not in parking mode
The camera is not getting a permanent live. Either the permanent wire is on an ignition fuse, or the kit’s voltage cut-off is set too high.
Test each fuse with the ignition off. A permanent fuse still shows around 12V. An ignition fuse shows nothing. Move the wires accordingly. See parking mode not working for the full checklist.
Symptom: camera stays on all the time and drains the battery
Both wires are on permanent fuses, or the ignition wire is on a fuse that stays live for a long time after the car is off. Some modern cars keep certain circuits awake for a while after locking.
Move the ignition wire to a fuse that switches off with the ignition. Then set a sensible voltage cut-off. Our guide to dash cam battery drain has more detail.
Symptom: fuse keeps blowing
This means too much current is going through, or there is a short.
- Wrong fuse rating. Use the rating the kit asks for in the tap’s camera slot, usually a small value. Do not fit a bigger one to “stop it blowing”.
- Damaged cable. A wire pinched behind trim or rubbing on metal can short. Look along the whole run.
- Fuse tap backwards. This can put the full circuit load through the small camera fuse.
- Tapped into a critical circuit. Never tap airbag, ABS, ECU or other safety circuits. Use something low risk like a power socket or sunroof fuse.
Symptom: car warning lights after the install
On some newer vehicles, tapping the wrong fuse or briefly shorting a circuit during the install can log fault codes. Remove the tap, check the fuse, and have the codes read and cleared with a diagnostic tool. If lights stay on, get it checked properly.
Symptom: radio interference after hardwiring
A poor earth or a noisy kit can cause DAB dropouts. See our guide to dash cam interfering with DAB radio.
Doing installs across a fleet
When you are fitting cameras to ten or fifty vehicles, inconsistent installs become a real cost. Each different fuse choice is a different fault waiting to happen.
Fleet cameras should be fitted to a standard, documented install per vehicle model, with each camera checked online before the vehicle goes back out. Connected cameras make that easy because you can see whether each one is powered and recording from the dashboard.
You can see how we approach this on our connected dash cameras page.
Summary
Check the earth, the tap direction and the fuse choice first. Most hardwire problems are one of those three. Never upsize a fuse to stop it blowing.