Safest fuses to tap for a 3 wire dash cam on a VW Golf Mk7 (2017)

Question

On A 2017, right hand drive Golf Mk7, what are the "safest choices" to tap when installing a 3 wire dash camera hard wire kit using piggyback blade adapter.

• Wire 1 requires always on power for parking detection
• Wire 2 requires ignition only power for recording while driving
• Wire 3 connects to the chassis stud.

By safest, I means fuses that do not power systems required for the vehicle's basic functions, such as breaks and steering, or critical safety systems such as air bags.

Alternatively, are there any fuses that should not be tapped under any curcumstances.

I specify want to avoid using the cigarette lighter power supply as this has been converted into a power breakout for another device, and I want it on a separate supply from the dash cam so that if one fails I still have a separate in cabin power supply.

I have seen multiple conflicting tutorials on which fuses to use, most from left hand drive vehicles.

Answer 1

I believe you are thinking about this wrong, mainly because the side you want to tap is the power side of the fuse. This is the side of the fuse power is delivered to it. If you use the opposite side, you're actually using the fuse as well, which can cause it to be overloaded with the camera's draw as well as the vehicle accessory draw. Here's what you need to do instead.

First, you need inline fuses for your camera on both sides (always active and keyed on) wires. This is to protect your device and the vehicle.

Next, with a multimeter and the vehicle keyed off, start checking the fuses for power. This will tell you whether the circuit is live or not with the key off. Check several fuses and find an active one which has the highest value for fuse protection. To figure out which side the power is actually coming from, pull the fuse and check the slots to see which side is powered. This is the side you want to tap off of so you're not overloading the fuse in the panel.

You'll want to use a larger fused circuit, like the 30A or 40A fuses, for your keyed on power source. This is because this circuit is rated for a higher load and can most likely handle it. Once again, find the powered side of the fuse and use it for your fuse tap.

Depending on what type of fuse tap you're using will dictate how it's installed. There are two primary types I'm aware of. First is like this:

This would go on the powered side as I suggested and slips over the leg of the fuse. The second type is like this:

The wired side of the tap would go to the powered side of the fuse. Remember, if using this type, you still need a separate inline fuse so as to protect the vehicle, vehicle accessory, and camera.

For the third wire, you can utilize any grounding (earth) source you can find. You may have to run a ground wire if the camera wire is not long enough.

Answer 2

One way to determine which fuses are always HOT and other fuses switched on with ignition would be separating them to two types of circuits. For always ON power; headlights, fog lights, brake lights. For switched power; everything else (seat heater, wiper washer, defrost, hvac blower, ac, etc.. There may be empty slots with either HOT or switched power to choose from. Using a multimeter will help. There should be a fuse guide embossed into the fuse cover as well as owner's manual. If cabin fuses are installed, more choices. Choose the largest fused circuit for wire-1/HOT and wire-2/switched power. I'm guessing dashcams draw less than a few amps and shouldn't strain 10/15/20/25/30/40 amp wired circuits.