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How to avoid Common Wiring Mistakes and correctly wire your car electronics – Jay’s Tech Tips #30

August 28, 2019

Hi I’m Jay from Real Street Performance. Today, we’re going to talk about some common wiring problems, and how to avoid them. The problem areas that we’re going to discuss are the connections, the wire size, the relays and the fuses. I avoid using the insulated connectors because it’s a split barrel clamp and when you clamp it down it’s liable to open up instead of crimp around the wire completely. Instead I like to use the full barrel connector. If crimped correctly, it totally encapsulates the wire. So the wire can’t pull out. If I am going to use a split end, where it can open up around the wire, then I’ll crimp the wire. And then I’ll heat it up and melt some solder onto it. And then use some heat shrink. Because the isolated connector doesn’t give you the visual of seeing how the connection is actually made, you can have a problem with an isolated connector just because you’ve used it incorrectly. They can work, but it’s easier to use the materials that I’m going to talk about today to make sure that you have a 100% good connections throughout your system. When using a non-insulated full barrel connector, you can be sure that the connection is made 100%. Once you’re done checking to make sure that your crimped correctly, you can slide some heat shrink over it to isolate it from the other wires and to seal it from the weather. Another common problem area Is when you have to pin your own connectors. If you’re Installing a different style map sensor or a different set of injectors, you may need to change the connector end. There’s a special type of pliers that is used to crimp these types of connectors and it’s wedges the wire down in between both sides of the connector to make sure that they’ve made a very good contact. If you prefer soldering, you should follow these steps to keep you out of trouble. Strip off about a quarter inch of the wire sheathing. Open the wire up in the shape of a V. Join it together with its mating wire. Twist the 2 together. Heat the wire with the soldering iron not the solder. As the wire reaches the proper temperature, the solder will melt in through the wire and you won’t have this globby mess of solder when you’re done. Then you can slide your heat shrink over it. It should look like this when you’re done. In respect to keeping the tech tip short in a manageable amount of time, we’re not going to go much into wire size. You need to understand the current or amperage draw that the device you’re wiring into the car uses. And then you can google around and find what size wire you need to be using. If you use a small wire on a large device, you’re going to have a large problem. So avoid that by just understanding how much energy the component needs, and then feeding it with the appropriate size wire. I recommend that you’re using fuses to isolate your aftermarket device from your factory system. This is a very simple way to avoid creating problems for your factory vehicle. Put the fuse near the power source and not near the device. If you short the wire out and the power source is at the front of the car and the device Is at the back of the car with the fuse, that length of wire Is going to be cooking. Versus if you have a problem with the wiring and the fuse blows at the power source, the whole device, the whole wiring and all of it is protected by that fuse circuit. So make sure that the fuse is near the power source. I recommend that you’re using a relay for any of your larger devices such as cooling fans, nitrous kit, fuel pump. The relay is not complicated to wire in. There’s generally 4 pins that you’re going to be concerned about. 30 will be a fused 12-Volt source. 87 will be the output going to the device. 85 will be a ground. It can go to a clean chassis ground, a battery ground, or a switched ground via your aftermarket ECU or hob switch. And the switched 12 volts is going to go to the 86 pin. Switched 12 volts means guys that it’s only key on power. If you wire up something to an aftermarket ECU or an aftermarket system where the 30 pin and 86 pin both have power all the time, you’re going to make for some strange problems for yourself. So do yourself a favor. Make sure switched 12 volts is indeed switched 12 volts on the 86 pin. I’ve seen way too many wiring mistakes to cover in 1 video. These are just some of the common mistakes I see. come to the shop, and I’d like to help you avoid them. Hopefully seeing them here will prevent you from running, into the same problems that other people did. Thanks and have a good week.


  • Reply Channing Kelso July 17, 2015 at 10:13 pm

    I wish I could do an apprenticeship with j. love the videos!

  • Reply robfrmny21 July 17, 2015 at 10:21 pm

    Using a fuse helps you avoid problems yes like a fire and damage to the powered component

  • Reply Erik Benedikt July 18, 2015 at 4:42 pm

    Just watched all 30 videos! Thanks for making these! Very good info!

  • Reply Mikegsx21 July 25, 2015 at 1:27 pm

    love the tech tips videos!

  • Reply Santiago M July 26, 2015 at 10:48 pm

    I would like to say that you guy's are awesome there at realstreetperformance, I hope to soon be sending you my block/engine for my Mk3 supra that will be fitted w/the famous 2JZGTE.she's ready as well as i am to see the streets again… Jay you are the man when it comes to building. Perfection is all I see in your videos. Great work dude!

  • Reply vangsti559 November 13, 2015 at 7:08 pm

    Great video jay. Learn so much. Keep it up.

  • Reply nazim multani January 15, 2016 at 4:12 pm

    Very nice

  • Reply nazim multani January 15, 2016 at 4:13 pm

    I want to know can network how to diagnose

  • Reply Ian Heller March 14, 2016 at 11:18 am

    this might be a stupid question, but what is the 86 pin?

  • Reply AdamAndMeisha May 15, 2016 at 9:01 am

    Great videos. More please.

  • Reply Driveway Marvels December 7, 2016 at 12:45 pm

    Thank you very much. Very informative.

  • Reply RD2FuelSystems April 12, 2017 at 4:06 pm

    that red cable fuse holder advertised as a 12gauge but it's a 14gauge. it's a peace of Chinese shit melting fuse holder. won't even hold 20amps

  • Reply averyvm1 April 20, 2017 at 6:46 pm

    Where's a good place to source those naked non-insulated connectors?

  • Reply Jessi Thom April 23, 2017 at 5:49 am

    Just look for Unflexal workouts. You will find there the best workouts instructions.

  • Reply Jester Mclarpet August 7, 2017 at 10:10 pm

    Never run undersize wires – you wouldn't like a sparky to do that to your house would you ?

  • Reply Some Dude August 18, 2017 at 8:07 pm

    these vids must be new. I don't recall them but I'm binge watching EVERY SINGLE ONE! πŸ™‚

  • Reply R Mack December 20, 2017 at 3:53 am

    Once had a telephone repair man come in and ask for a switch (quote) "to break one wire". When I asked about the voltage and current levels he was dealing with so I could get him the correct rated switch, he said: "I got 12 volts of current and no amps". TRUE STORY!

  • Reply The Burden January 17, 2018 at 4:19 am

    Hey, YOU. This is an important video. Pay attention!

  • Reply Kari Sinkko January 30, 2018 at 6:23 am

    Great video.

  • Reply Sean Kaine April 3, 2018 at 9:14 pm

    Classic if you're going to use a small wire on a large device you're going to have a large problem😁😁😁😁

  • Reply raredesign February 18, 2019 at 11:40 pm

    excellent video sir! Thank you.

  • Reply Enrico Malinovic February 19, 2019 at 2:30 pm


  • Reply John Terpack February 22, 2019 at 1:51 pm

    I wish you had included a warning about those "no splice" connectors. Every time I climb under the dash of a new toy and find a handful of those I want to track down the previous owner and beat him upside his head.

  • Reply gazon Charles July 8, 2019 at 3:22 am

    Appreciate u bro always learn something new

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