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I’m trying to install a dash cam with the parking option that requires a line to be hooked up to constant power and one to ignition on. Are there any empty fuse slots that provide constant power and ignition? Or would it be better to just add a add a fuse.
I can't answer the first question for you without researching or just going out to my car and testing the slots themselves, however, I personally would just add my own fuse. Just be sure to use the proper gauge wiring with the right fuse.
There is not a hardwire kit available for it?
I'm looking to get a dashcam, haven't done my own research yet, do you mind sharing what model you purchased?
I purchased a Rexing v3 plus. It does have a hard wire kit and it has fuses attached at the end so you just plug it into existing unused slots. But I’m not sure how to figure out which ones would have power already going to it. I was thinking of using a add a fuse which would go into a current slot that’s being used like the cig lighter slot and would add an additional fuse slot to the same slot. But if it is possible I would like to avoid doing that.
I’m trying to install a dash cam with the parking option that requires a line to be hooked up to constant power and one to ignition on. Are there any empty fuse slots that provide constant power and ignition? Or would it be better to just add a add a fuse.
Originally Posted by esonu
I purchased a Rexing v3 plus. It does have a hard wire kit and it has fuses attached at the end so you just plug it into existing unused slots. But I’m not sure how to figure out which ones would have power already going to it. I was thinking of using a add a fuse which would go into a current slot that’s being used like the cig lighter slot and would add an additional fuse slot to the same slot. But if it is possible I would like to avoid doing that.
Do you have a multimeter?
You can purchase for as little as $17.
For a constant current fuse, try testing the Hazard WarningFuse with the ignition switched off.
For a switched fuse, try testing the Shade Fuse, first with the ignition switched off, then with the ignition switched on.
Fuse Polarity Switch the multimeter on.
Rotate the dial to the DC Voltage Mode.
Using pliers, remove the fuse you want to test. Look close and you will see two tiny copper electrodes: left and right.
One of those electrodes will be red positive and carry the current from the battery, while the other electrode will be black negative to return the current to the battery.
Place the red electrode pen to test the left copper electrode, and place the black negative electrode pen to the big ground screw at the bottom of the photo below, and see what current reading you get?
Then place the red electrode pen to test the right copper electrode, and again place the black negative electrode pen to the big screw at the bottom of the photo below to return the current to the negative terminal of the battery, and see what current reading you get?
The positive copper terminal will generate a 12 V reading on the multimeter.
The negative copper terminal will generate a 0 V reading on the multimeter.
So which column of copper terminals [left or right] is positive, and which is negative?
NB.
Understand that the red wire carries current from the battery to the device.
Also understand that the black wire is supposed to carry a return current from the device back to the negative black terminal of the battery.
However, if auto manufacturers did this, we would have tens of meters of black return cabling!
Because most cars are built with high tensile steel chassis which conduct electric current, the high tensile steel chassis itself is used to return the current to the negative terminal of the battery, saving many many meters of black return cabling.
The 12 V current is too low to electrocute the occupants.
Hence, to complete the circuit, you only have to place the black negative pen of the multimeter to the big hexagonal ground nut at the bottom of the photo below.
An all aluminum or carbon fiber chassis vehicle would need black return cabling to the negative terminal of the battery.
Constant vs Switched Fuses
Thus, having determined the polarity [+/-] of the two copper electrodes, find out if that fuse is truly constant, or truly switched by testing the fuse with the ignition off, and testing again with the ignition on.
A constant fuse will always register a 12 V current on the multimeter, regardless of whether the ignition is on or off.
A switched fuse will only register a 12 V current on the multimeter when the ignition is switched on.
NB
Constant and switched fuses don't always make sense; they aren't what they appear to be.
For example, a windscreen wiper fuse you'd expect to be a "switched-type" because it can only be operated with the ignition on, but you may find that your windscreen wiper fuse is constant! Thus, the only way to ascertain if a fuse is truly constant or truly switched is to test it with a multimeter!
Fuse Taps
You must purchase a fuse tap with the same fuse type as your vehicle.
Most Toyotas use the Low Profile Mini Type fuse pictured below.
Next step is with the correct positive to negative polarity, to plug in a fuse tap.
Unfortunately, you cannot plug the fuse tap in with any +/- polarity you feel like.
The red wire from the fuse tap to your dashcam will either pass to the left, or pass to the right; the fuse tap in the photo below is carrying current to the right.
If the positive copper electrode is on the left, then you would plug in the fuse tap like the last photo below, with the positive current passing up the fuse tap on the left, and returning to the negative terminal of the battery by travelling down the right hand side pin below with the red arrows.
Notice how the fuse tap taps current via the blue arrows to a 2nd fuse to ultimately pass through the right hand side red wire below to your dashcam?
Thus, you would plug the manufacturer's original fuse into the lower slot of the fuse tap like the last photo below.
Fuse Types
Meanwhile you must purchase a new fuse for your dashcam.
Toyotas generally use Low Profile Mini fuses below.
Fuse Sizes
You must find out what is the maximum current draw of your dashcam; use the spec sheet. Normally it is well under 5 amps.
You could purchase a 5 Amp fuse of the same type for Toyota products and insert it into the upper fuse slot of the fuse tap with blue arrows like the photo below.
Fuses are color coded depending on the amperage rating.
NB
If you use a fuse with a lower amperage rating than your dashcam, then the fuse will melt, smoke, and your dashcam will stop working.
You must use a fuse with a slightly higher amperage rating than your dashcam's maximum current draw; look at your dashcam's spec sheet.
If you use too high a fuse like 10-15 A, your dashcam will certainly work, but very high 10-15 A currents can potentially destroy your low current draw dashcam, long before they melt the fuse; the fuse is there to protect your dashcam from excessively high currents.
Your dashcam should now be ready to go....
Last edited by peteharvey; Jan 27, 2021 at 05:06 PM.
That’s some great information.. I appreciate the assistance. I do have a multimeter in the garage so I will try this out this weekend. Learning experience for sure.
Thank you again for all the information.
For a constant current fuse, try testing the Hazard WarningFuse with the ignition switched off.
For a switched fuse, try testing the Shade Fuse, first with the ignition switched off, then with the ignition switched on.
Switch the multimeter on.
Rotate the dial to the DC Voltage Mode.
Remove the fuse you want to test.
Now you will see two copper electrodes: left and right.
One of those electrodes will be positive and carry the current, while the other electrode will be negative to return the current to the battery.
Place the red electrode pen to the left pin hole, and place the black negative electrode pen to the big screw at the bottom of the photo below.
NB.
Understand that the red wire carries current from the battery to the device.
Also understand that the black wire is supposed to carry a return current from the device back to the negative black terminal of the battery.
However, if auto manufacturers did this, we would have tens of meters of black return cabling!
An all aluminium or carbon fiber car would need black return cabling to the negative terminal of the battery.
Because most cars are built with high tensile steel chassis which conduct electric current, the high tensile steel chassis itself is used to return the current to the negative terminal of the battery, saving many many meters of black return cabling.
Hence, to complete the circuit, you only have to place the black negative pen of the multimeter to the big hexagonal nut at the bottom of the photo above.
NB
Constant and switched fuses don't always make sense; they aren't what they appear to be.
For example, a windscreen wiper fuse you'd expect to be a "switched-type" because it can only be operated with the ignition on, but you may find that your windscreen wiper fuse is constant!
Thus, the only way to ascertain if a fuse is truly constant or truly switched is to test it with a multimeter!
Thus, having determined the polarity [+/-] of the two copper electrodes, find out if that fuse is truly constant, or truly switched?
Next step is to plug a fuse tap in with the correct positive to negative polarity.
Unfortunately, you cannot plug the fuse tap in with any +/- polarity you feel like.
The red wire from the fuse tap to your dashcam will either pass to the left, or pass to the right; the fuse tap in the photo below is carrying current to the right.
If the positive copper electrode is on the left, then you would plug in the fuse tap like the photo below, with the positive current passing up the fuse tap on the left, and returning to the negative terminal of the battery by travelling down the right hand side pin below with the red arrows.
Notice how the fuse tap taps current via the blue arrows to a 2nd fuse to ultimately pass through the right hand side red wire below to your dashcam?
Thus, you would plug the manufacturer's original fuse into the lower slot of the fuse tap below.
Meanwhile you must purchase a new fuse for your dashcam.
Toyotas generally use Low Profile Mini fuses below.
You must find out what is the maximum current draw of your dashcam. Normally it is well under 5 amps.
You could purchase a 5 Amp fuse of the same type for Toyota products and insert it into the upper fuse slot with blue arrows below.
Fuses are color coded depending on the amperage rating.
NB
If you use a fuse with a lower amperage rating than your dashcam, then the fuse will immediately melt, smoke, and your dashcam will immediately stop working.
You must use a fuse with a higher amperage rating than your dashcam's maximum current draw; look at your dashcam's spec sheet.
If you use too high a fuse like 10 A or 15 A, then your dashcam will certainly work, but then very high 10/15 A currents can potentially destroy your low current draw dash cam, long before they melt the fuse.
The fuse is there to protect your dashcam from excessively high currents.
Well seems like our cars have unused slots in the passenger side. If I shouldn’t be using this please let me know. Hopefully it was made for accessories to be added. But I found one with constant power(yellow) and one with ignition on(red). Works perfectly fine.
Fuse slot question
