CURT56377 Vehicle-Side Custom 4-Pin Trailer Wiring Harness, Select Mazda CX-5 , Black

I had my Mazda dealer handle installation of this and a Curt 2" receiver on a new 2021 CX-5 Signature I just purchased.I'm familiar with Curt products as I've owned them before and every one was well made.The tech who installed this said it was a great choice and he said the installation went very easy and logically as well.The Tech and I discussed any shortcuts to the install and he emphasized not to take a shortcut and splice to the hot wire to the rear 12V cigarette receptacle as does Curt NOT want you to do this per the installation instructions. The hot wire should go to the battery location under the hood.My Utility Trailer uses all regular bulbs rather than low power LEDs and the Tech said it is safer and more reliable to hot wire to the battery due to the higher demand on that circuit branch. Given I might use that rear cirgarette lighter location for other accessories, that all makes sense. Maybe I'll convert my trailer to all LEDs at some point.Both the Service Advisor and the Tech warned me not to take any shortcuts and they wanted to adhere to Curt's Installation instructions for this harness, including the black hot wire that has to run to the front of the vehicle. It was, -By the Book, period!-There is plenty length for the harness connection and everything is stored in the rear wheel-well where the spare tire is located.No complaints and when a Mazda tech says a product is great and the install of it was the same, that's good enough for me!5 Stars all around and no complaints at all.

Well designed harness that includes a mini transformer so it can be used for trailer lights that are incandescent or LED.NOT easy to install. Many interior panels must be removed and a power wire must be “snaked” from the battery or positive pole of a fuse box to the rear of the vehicle. Once installed, it works perfectly.

We've been using our hitch for over a year now with bike and motorcycle racks, but finally got around installing this wiring kit. I love that you don't have to splice any of the factory wiring. Easy plug and play. Instead of running the Positive power wire back to the battery, I purchased a cheap 12v extension plug with fuse and ran the wire to the passenger side with the tail light wiring. The few times that I plan to tow and need trailer lighting, I will simply plug in the 12v plug to the rear accessory outlet. The low power draw on this has no issue running through the accessory plug. I hid the flat 4 plug in the driver side storage cubby so we just pull it out and run it out the lift gate when we need it.12v extension lead I used was https://amzn.to/40bL5X3

This adapter is well made and overall pretty easy to install. Of course running the power wire from the battery is a pain, but it can be done without a lift. I was able to squeeze under the car and zip tie the power wire to the existing support and then put the plate that protects that area back on. I used the Uhaul video and it walks you through the entire install in great detail. They use an upgraded battery cable but it's pretty self explanatory how to use the one that comes in this kit.I was able to install this in about an hour. I leave it inside the car under the trunk mat and just run it out and hook it up and then close the trunk over the wires when in use. You can also mount it outside the car, but then you'll need to worry about keeping the connection clean. As little as we use it I'd rather keep it out of the elements until needed. The trunk does not damage the wires when closed.

I installed this in a customers mazda and it worked great. Curt is my go to for all trailer wiring because it always works, first time.Tip: most Mazdas have a adequate power supply at the cigarette power outlet in the trunk. Saves you a run to the battery!

I originally watched a video (the wrong part number video) that stated that my 2018 Mazda CX-5 did not need to connect any wires directly to the battery so I ordered it and found out that it does need to be connected to the battery, so, I phoned Curt Support and they stated that the reason that you have to connect to the battery is because the rear tail lights do NOT provide enough power to light up the trailer lights. ***TOTALLY MAKES SENSE*** As far as the install, it went well and only needed to run along the doors trim and through an existing round grommet to the left of the brake pedal, I removed the positive screw holding the battery clamp to the terminal and placed the included yellow wire end of the black wire to the back of the screw and re-attached the nut and tightened down. I did purchase a tester for $5 to check the connection. Overall...happy with the clean installation!

Install was not complicated. I did find a video specifically for my car, however. You can check YouTube to see if there are hitch wiring videos for your car too. One thing though, I did not have a crimper so that made it hard to connect some wires and it’s not worth it to buy a dedicated crimper. A different option other than having to crimp it would make it perfect.

I'll echo what others have already stated: no need to run the power lead all the way to the engine bay, just tap off the accessory socket on the passenger side rear. Wish CURT would update their harness to include the proper plug/splice to do this, because you'll be forced to cut/splice/solder yourself.Definitely keep the 10A fuse because it's much easier to find/replace these normal size blade fuses vs the minis under the dash.Also I just kept the plug/cord in the spare tire well and run it underneath/out the hatch. The weather stripping smashes enough to not pinch the flat wire. No need to run it out the underside.

This product worked well and was not too hard to install if you are mechanical inclined

Funciona perfecto

Installed in 15 mins. The AC cigarette lighter plug on the right side is easy to splice for 12v.

Installed in a 2021 CX-5 with no issues. Watched YT before which helped. Running LEDs so should work fine. Very happy with the product.

Good product, fits the vehicle, but not so easy to install. You have to partially remove some cover panels from trunk and run a + wire from battery, under the vehicle into the trunk.