Tricking A JK - Randy’s Electrical CornerPosted in How To: Electrical on August 12, 2014 0) (
I feel like a witch doctor with a bone stuck through my nose dancing on coals waving a freshly dead chicken over my head and chanting mumbo-jumbo. I might have to stop playing with Jeeps. My feet can’t take the heat, I like my chicken on the barbeque where it belongs, and I really don’t want a bone stuck through my nose. I don’t know how I get myself into these things. Maybe I really am the dummy that Joy always says I am. But, I’m just trying for some good karma here like Earl always does, so when Trasborg asked me to play inside the dash of Jp’s ’07 JK I said, “sure, why not?”
But Jeeps are just getting too complicated. I guess maybe I’m putting the cart in front of the horse here because I’m talking about modifying two installations I haven’t covered in these pages yet. But, truth be told, I’m still playing with both installs and looking for more info about them so I can’t really talk about either one yet. Oh yeah, complicated Jeeps. These ’07-present Wranglers that you guys call JKs are way too complex. They don’t just use the normal 12 volts to turn things on and off—they talk in computer language or something (editor’s note: CANbus) to turn every part on or in the Jeep. Did you know that if you replace the headlights or the factory radio, the Jeep computer throws a code? It doesn’t light up the dashboard light, but the code is there in the system just the same. Did you know that if you take the stereo out of one Jeep and try to put it in another, it won’t work?
I didn’t know any of that, and once I started tinkering, that witch doctor thing came to me. I finally figured it out, but it was more trial and error than anything else. Like I’ve been saying all along, I’ve messed up more electrical stuff than many people have ever played with, so I’ve learned a few things about how to mess with stuff. I thought it would be neat to show you one way I experiment that sometimes keeps me from killing electrical things. At the same time, I figured I’d show you a couple of neat tricks with some aftermarket parts to get them to do things that their manufacturer’s never really intended for them to do.
I had two things I was trying to do here. The first was I wanted to watch DVDs on the new Sony XAV-712HD radio from Quadratec while Trasborg was driving, but it was somehow locked out. The other thing I was trying to do was get the illumination on the switches in the sPOD to light up automagically when he turned on the headlights. Neither company ever intended for either thing to happen, but I thought it would be cool if it was possible to make it happen. So here’s what I did; so far nothing has blown up, and the Jeep hasn’t freaked out in the weeks since I did it.
Once that was solved, it was time to solder. Always tin your tip before just diving in. Notice the blue wire heading up in the picture? That’s another test wire and fuse, but more on that later.
When I don’t know if something I am doing is going to work, I put a fuse in it. In this case, I found on the interwebs that if you grounded this wire (which should have been light green, but the Quadratec harness had changed it to a blue wire with a yellow stripe) then the stereo would play DVDs while the Jeep was moving (editor’s note: Don’t do this at home). But because this XAV-713HD unit was brand new, there was no specific information about it. So, I took a fuse holder, stuffed it with the smallest fuse I could, and tested for what I was trying to do. It ended up working, and I didn’t pop the fuse, the radio or anything else.
Once I’d figured out that it was going to work like I hoped it would, it was time to solder the joint and heat shrink it. Always heat the work (editor’s note: In this case, the wire) and not the solder. Once that was done, I moved on to the lighting issue. The Quadratec adapter harness came with a CANbus interface box, and I tapped into all these wires between the box and the new radio. I’m not sure if any of this would work if you tried to do it on the other side of the box, but the sPOD people tell me it’s a really bad idea to even try.
The sPOD provides a really easy way to add accessories to a JK that doesn’t hack into the factory wiring at all. Any factory wiring hacking in these things could lead to weird flickers and electrical problems. And I’m not just talking at the place you hacked. Like hack the radio in, and your taillights might stop working. The sPOD features Carlintong-style on/off switches that have illumination for both the accessory and for nighttime illumination. As delivered, it has a small push-button switch to turn on the nighttime illumination. Using the same fuse and jumper wire thing I figured out I could jump from the orange wire (editor’s note: illumination) feeding the radio to the sPOD push button and have the lights come on when Trasborg turns on the headlights.