JD1912 Car Relay Harness 12V 40A 4 Pin SPST 12AWG Harness Sockets with Color-Labeled Wires for Automotive Truck Van Motorcycle Boat (Pack of 2)

works well, all I need is one but will use the other ones someday.

I used these for the circuitry on 1970's Jeep Wagoneer rear power window and they worked flawlessly. I would EASILY buy these again. The recepticles are well made and include small metal mounting tabs which I did not use. The relays work. The wiring is true to the stated gauge sizing. I paid about $8 for the pair of these in April 2025. At $4 each, these are a good value assuming they last. These will be getting near daily use so I will report back, especially if these prove to be unreliable.

it was perfect worked like it should glad it came with 2 bc i messed up the wiring om the first one i would recommend getting this product

It’s exactly what it is and worked well.

Just FYI - The relay picture on Amazon shows there is no diode between 85 and 86, but the actual relay shows there is. So don’t reverse polarity and make sure 86 is positive.

Used this relay to wire up the air compressor for my air bag suspension on my pickup, and it worked flawlessly. The color-labeled wires made installation super straightforward, and the 12AWG wiring feels solid and well-made. Handles the load without any issues, and it gave me peace of mind knowing the compressor is properly wired and protected. Great value for the quality—definitely recommend it for any automotive accessory setup.

Worked great for my headlight relays!

Two for the price of one is always a great deal! The price is very good for this power relay switch. The device is properly sealed in a case to make it waterproof. It comes with a connector that likewise seals well when plugged in to the relay.This is rated perfectly to carry the current and power needs for all of my motorcycle accessories. I wanted to isolate all of my add-ons so that when the bike sits dormant the drain on the battery is greatly reduced. My circuit includes this relay between my accessory terminal to a power distribution block with fuses. When the motorcycle is turned on the relay engages sending power to the distribution block. The block has six accessories wired with individual fuses on each circuit. When the relay engages power is available to the block and sent to each of the six accessories.By isolating the power to the accessories with the relay they cannot draw even a trickle current from the battery when the motorcycle is powered off.The relay has a diagram on the top of the case to show the circuit but these are stamped into the case and very difficult to read. More importantly, the relay does NOT come with any directions whatever! There are four leads/wires coming from the included plug which are color coded. I was able to determine by testing with a meter which lead was Common, Positive, Line and Load. The plug terminals are uniquely oriented so that it is not possible to insert the relay incorrectly which I deeply appreciated.You need to have a thorough understanding of circuitry to properly install and use this. Two wires power the relay itself, the other two break/complete your desired circuit power. Make sure your power demand is aligned with the ratings of this relay. It is robust and spec'd for most common power needs for outdoor vehicle accessories.NOTE: The photo shows three items, the relay and plug which are included, and the power distribution block with IS NOT included. I just showed to illustrate my setup.Prior to installing this relay and distribution block I had 7 or 8 different wires and terminals connected to the positive/negative terminals on the battery. What a rats nest! This new circuit setup reduces the wires directly connected to the battery, provides circuit protection and clean wire routing. In operation the relay works flawlessly. Aside from the lack of instructions I feel this is a great value as the product works well, comes with the necessary plug and you get TWO of each.