2012 Mazda5 Dash Cam Wiring - Which fuse to use?

[12phive]

I recently hard-wired (sort of) a dash cam using an add-a-circuit (see photo) at the interior fuse box connected to a 12V female socket (see photo), into which went the cam's 12V male plug. I chose the seat warmer' ACC fuse, but I seem to have chosen poorly. Seat warmers stopped working after a while. Inspection revealed that the add-a-circuit tried to plastic weld itself to the fuse box while blowing the seat warmer fuse. Luckily everything came apart and a new seat warmer fuse was able to be returned to the original fuse slot. Everything stock works as normal with no further issues. I have not reconnected the dash cam circuit.

Inspected the wiring setup. Made sure grounding was correct - 12V socket black to car body. Connections were done with crimp-style connectors. No loose, frayed, or stray wires. Correct amperage fuses were used. All fuses and add-a-circuit were seated correctly. Electrical tape wrap on the 12V plug connection.

This particular cam's 12V power plug has a large rectangular housing for the e-guts, hence this setup choice. I am loth to disassemble the plug and try to wire it directly into an accessory circuit, e.g. the overhead dash light. I like the add-a-circuit + add'l 12V socket at the fuse box idea, and I already have the wiring cleanly tucked/fished.

Can I use a different fuse circuit for this same setup - cameral needs a 10A circuit?

• If so which fuse would be best, or...
• will I risk the same thing happening?

If this is not a viable solution, what is the next best solution? While a novice at electronic hijinx, I am comfortable with a small amount of soldering/wiring work.

Finally, I am having a hard time wrapping my head around how the load of both the seat warmers' 15A circuit and the dash cam's 10A circuit resulted in the warmer fuse blowing out, given that they should have maintained separate circuits. Was it simply a matter of the two loads (25A total) overheating the plastic add-a-circuit item at the fuse box's single slot for the 15A warmers, eventually creating a short on the add-a-circuit's warmer fuse? If anyone wants to bother to confirm or explain what happened, that would be much appreciated.

Many thanks in advance for any help/advice you can offer!

 

[hleboklop]

What's the camera model? Generally, a dash camera would only consume about 10-15W tops, which means, that even a 2A fuse would be sufficient.

If the camera comes with the wiring kit, you might want to wire BAT to MAIN relay fuse and ACC to Acessories Switch fuse. I would totally recommend wiring the camera with the wiring kit, as this would extend the camera functionality, such as "don't fully drain the battery" and "graceful shutdown for the camera". Also, check out the timer relay, here, it's very useful for the cause.

In the past, I did all this and that and other setups. You could power your camera from the OBD2 port even.

In my personal opinion, the best option would be tapping into the power supply for the stereo system. Usually, when I retrofit a car with an android stereo, I use the same connector to provide power to the dash camera. This way, the camera is fused via stereo circuit and doesn't tend to get the power fluctuations that other circuits are prone to.

 

[negusm]

Those "add-a-circuit" devices...are the fuses in parallel or are they in series?

If they are in *series*, then the larger fuse MUST be the factory fuse and MUST go in the factory fuse location of that device. I'll tell you right now, heating elements are notoriously power hungry and may get super close to that 15A rating all by themselves. If the camera need 2A...it should be fine but you need to know how much it takes and how much the heated seats take.

If the fuses are in *parallel*, then there is a risk of overload. Adding a 15A fuse and a 10A fuse with one of those things makes it a 25A circuit as far as the fuse box is concerned. You would need to make one fuse 5A and one fuse 10A. Then the entire circuit is back to 15A. The Fuse box will be happy.

Take your multimeter and test that device and make sure the fuses are in series and not in parallel.

 

[hleboklop]

These add-a-circuit devices are always wired in parallel.

Finally, I am having a hard time wrapping my head around how the load of both the seat warmers' 15A circuit and the dash cam's 10A circuit resulted in the warmer fuse blowing out, given that they should have maintained separate circuits.

Are you absolutely sure you plugged the 10A for the camera addon and 15A for the heater?
What if you did the opposite, resulting a 10A for where 15A should be? Just a thought.

 

[negusm]

Parallel?

Then there is a risk that the manufacturer didn't expect that any more than 15A was going to go through that fuse connection at the fuse box.

Adding the 10A circuit in parallel to a 15A circuit means you potentially have 25A going through the fuse box at that connection. This can explain why that area started melting.

 

[12phive]

These add-a-circuit devices are always wired in parallel.

Are you absolutely sure you plugged the 10A for the camera addon and 15A for the heater?
What if you did the opposite, resulting a 10A for where 15A should be? Just a thought.

I double checked instructions and installed as suggested - 99% certain I got the fuses in the right spot. Had I not, then the fuse that was too weak for the circuit would have blown. This did not happen, rather the spot on the fuse box where the add-a-circuit plugged in was the point that got too much juice. After reading this and the others, I believe the issue was too much total amperage for that fuse location when both the cam and the heaters were running.

 

[12phive]

Parallel?

Then there is a risk that the manufacturer didn't expect that any more than 15A was going to go through that fuse connection at the fuse box.

Adding the 10A circuit in parallel to a 15A circuit means you potentially have 25A going through the fuse box at that connection. This can explain why that area started melting.

Yeah this is likely the case. Too many amps through that fuse location. Will have to reexamine the add-a-circuit idea for this application.

 

[12phive]

Those "add-a-circuit" devices...are the fuses in parallel or are they in series?
...
If the fuses are in *parallel*, then there is a risk of overload. Adding a 15A fuse and a 10A fuse with one of those things makes it a 25A circuit as far as the fuse box is concerned. You would need to make one fuse 5A and one fuse 10A. Then the entire circuit is back to 15A. The Fuse box will be happy.

This might be a solution, but would the smaller fuses be able to handle the amps? The cam is probably very low draw, but the heaters are definitely not low draw. I guess I could give it a test run with just the heaters and a 10A fuse. If that holds, then adding a 5A for the cam should work. Thanks for the tip! Fingers crossed...

 

[teetee1]

I piggybacked the cigarette lighter fuse socket in the fuse box with the same fuse tap setup since the socket is only energized at the Acc. key position. It has been working for several years. Properly orienting the add-a-circuit fuse is important to get the power from the battery side to the load side on both the original and the add-on circuits, rather than only the original. 2:50 mark at using add a circuit fuse taps explains it.

I would avoid tapping into any heating circuits.

 

[negusm]

This might be a solution, but would the smaller fuses be able to handle the amps? The cam is probably very low draw, but the heaters are definitely not low draw. I guess I could give it a test run with just the heaters and a 10A fuse. If that holds, then adding a 5A for the cam should work. Thanks for the tip! Fingers crossed...

Better to blow a fuse than to melt stuff. If you switch it and the 10A heater fuse starts blowing. I would then find another circuit to draw from as the heating elements are requiring ALL of those 15A.

 

[turbonium959]

I did this on my 13 Sport a little over 3.5 years ago. Not sure why I tied it to a 15A fuse. I believe it was the lowest fuse that was also always powered when the engine is running. I threw some zip ties at this setup, to ensure that nothing came loose and seems to be doing well. My dashcam is Anker Roav C2. Its nothing super fancy, but its there.

 

[12phive]

I piggybacked the cigarette lighter fuse socket in the fuse box with the same fuse tap setup since the socket is only energized at the Acc. key position. It has been working for several years. Properly orienting the add-a-circuit fuse is important to get the power from the battery side to the load side on both the original and the add-on circuits, rather than only the original. 2:50 mark at using add a circuit fuse taps explains it.

I would avoid tapping into any heating circuits.

This is the route I used. "CIGAR" 15A accessory sockets (Dashboard) according to the book. Double checked orientation of the add-a-circuit plug as instructed. I could not find 7.5 amp fuses at any of the local auto parts stores - at least not in anything smaller than a $50+ bulk fuse pack. Used two 5A fuses in the add-a-circuit, and have had no issues with either the cam or the accessory socket. We only use that socket for charging phones via USB, and nothing draws more than 5A. If I need to use something with a greater draw, like an air pump, I can use the cargo compartment socket.

One obstacle was the too-clever plastic tabs that snap over the fuses once installed into the fuse box. Those interfered with seating the add-a-circuit plug, so I broke them off for that fuse location. It is a risk I am willing to take.

To wrap things up, everything works as intended with no loss of use or function. Many thanks to everyone that contributed! Next projects: horn upgrade and belt/tensioner replacement.

 

[Buckshot77]

Hello there just did a search as i am trying to do the same thing . I have a papago dashcam that was in my 2018 mazda 3 for years and i'm trying to use the same wiring harness i used to wire it now to my 2012 mazda 5 . I was a bit taken back on how difficult it is to access the plug in the firewall to get wires through there so i figure the passenger fuse panel would be the better way to go . I was going to tap into the Acc slot for this . However my question is for everyone who has done this where did you go with your ground wire ? I tried to test the fuse slots with a tester using the bare frame that sits around the fuse box and i cant get a reading here assuming that its just not good enough ground. Appreciate any tips for this as i also want to do the same for my radar/laser detector . In my Mazda 3 i just went through the firewall under the steering wheel and wired directly to the battery with a in line fuse and it worked no problem for years. I supposed going through the firewall is still an option but from what i can see is i would have to take the entire glovebox assembly out to even attempt that .