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ACC Fuse voltage in internal fusebox reads 12 volts on both terminals

I’m trying to hardwire a dash cam, I want it to turn on when the car is on and off otherwise. However -The dash cam won’t turn on when the acc wire is connected through a fuse tap. Further testing reveals:
-The cigarette lighter itself works only when the car is on (like it should - The car manual says this is an acc fuse)
-The dash cam WILL turn on when the constant wire is attached and will stay on if the car is turned off (this is a problem). HOWEVER the cigarette lighter still turns off when the car is off

I’m confused on how to proceed. Any advice??

Electrical noobie :slight_smile:

2 of my cars’ cig lighters are always on even when the ignition is off. What are these cars? I didn’t say. Don’t you think it would be useful if you told us what vehicle you are working on?

General advice… find a fairly large fuse, 10 15 or 20 amp, for something you think is controlled by the accessory switch. Test it, key on, key off. Once you find one that works when the key is on, remove that fuse, install a fuse tap. That is a device with 2 fuse sockets, one for the original accessory, one for your add on dash cam. The 2nd slot is for the cams much smaller fuse. Done.

Does your dash cam need both an always on connection and an accessory connection? What are you calling the constant wire? The one that needs to be attached to the always on battery connection?

Thanks Mustangman, its a Honda Civic 2006. The Car manual says that the cigarette lighters should be connected to ACC fuses (and true to this it only works when engine is running). The ACC wire is connected through a fuse tap and the original fuse is in the correct fuse socket - this much has been triple checked and verified.
My confusion is because:
-with power through the cigarette lighter - Cam works fine
-if connected through the constant wire of the hardwire kit to the ACC fuse - cam works even if car is off
-if connected through the ACC wire of the hardwire kit to the ACC fuse - cam won’t turn on.

Are you using a voltmeter to check the connections?

The hardwire kit has 3 wires; black grounding wire, red ACC wire and yellow Constant wire. According to instructions, the yellow Constant wire is to provide constant power if you want the cam to work in parking sentry mode when parked. (I have no need of this feature).

Yes, I’ve got a multimeter that I’m using to check the voltage readings.

You seem to be crossing terms here and confusing the description. I’ll try and decipher.

Seems like ACC means “accessory” but is not switched ignition. If there is 12v when the ignition is off, it is connected to the battery, not through the accessory no matter what it is labeled. Believe your multimeter, not the label. I think that might be the disconnect (pun intended) you and I are experiencing.

Hook the red wire from the cam to any fuse that is powered off when the ignition is off and powered on when the ignition is on… i.e. the cigarette lighter. If the fuse you are using is the cigarette lighter and it is switched with the ignition, great, use that fuse and fuse tap.

Thanks! I was treating both terms ACC and ‘switched ignition’ as the same until you clarified. So my accessory must be on constant power. :slight_smile:

I’m going to head out and give it another go on the car with your instructions. Its freezing cold out here in the MN, but I’m too enthusiastic to let that stop me. LOL. I’ll come back and update.

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Update. I followed your directions with both the Red and yellow wires and… …success!!

Some more detail - hopefully this is helpful to another noobie like me. With my hardwire kit, I was ignoring the constant power wire since I don’t plan to use the Sentry Mode feature. I was only interested in the dash cam running when the ignition is switched on. However it seems that the hardwire kit routes power through the Yellow Constant Power line only. It is only using the red wire to signal that the dash cam needs to be turned off/on. As soon as I had both wires connected, everything worked like a charm.

Thanks for all the help Mustangman!

Final Note: One thing that was confusing me (noted earlier) was that the fuses powering my cigarette lighters are getting constant power, but the cigarette lighters only work when the car is turned on. So maybe they are being controlled by a software interlock that cuts off power when the car is off? Not sure if this make sense?

There is probably a switch, relay or whatever after the fuses that cut off power.

I recommend one of these:

It has adequate settings that will suit your needs. It has a rechargeable battery, so it works when the car is off, and you can set it up for motion activation.

You can set it to record in three minute cycles, automatically erasing the oldest video as it records, so if you have it on the 1080p setting, you’re going to want to upgrade the SD card.