Draco-REX Posted October 24, 2010 Share Posted October 24, 2010 (Note: Wasn't sue if this fell under Performance or Maintennance how-tos, so mods feel free to move this) So, I was looking at my tail lights after buying my Leggy and I wasn't happy with what I saw. There were four bulbs behind red lenses, but two of them were jsut for turn signals. Why weren't they yellow? Well, they weren't carrying their weight. I'm a big fan of visible brake lights. They're essential to safety and with how many people seem to drive by sheer luck, I figure I can use all the help I can get. High contrast (Off to On instead of half-bright to full-bright) brake lights are also something I like to have at night. So all I have to do is get the upper pair to light up when the brakes are on and I'm happy. I jsut have to get the turn signals to turn on when the brakes are off, and turn off when the brakes are on. Should be a piece of cake. A couple relays and I'll be done. Fast forward two months. I finally came up with this: http://farm5.static.flickr.com/4153/5098530482_5fa52206d7_z.jpg Two relays per side and some fancy wiring. Unfortunately, there are a few problems. First, this would be noisy as hell. Brakes *click*, turn signal *klak**klak**klak*, both *clickklak**klak**klak*. Second, sharp-eyed folks will probably see that I'm severing the ground I need to trigger the DPDT relay. And third, the DPDT relay wouldn't have had enough draw to stop hyperflash. If I had implemented this, I'd likely have had a disco going on behind me. So, unhappy with my result, and knowing nothing about electronic components smaller than a relay, I contacted a friend of mine who does know all this stuff. For those on CentralOhioSubarus.com or DirtyImpreza.com he goes by Teslamaster. After outlining my goal and what little I had, I asked him to come up with a solution that I could piece together with an electronics store and a soldering iron. His reply made me hit my head against the wall: So I was drawing up a circuit for you when I realized I already have something that does just what you want installed in my car right now. It's the converter for my trailer lights. What made this worse is that I had the same box in my WRX for my race trailer. So early moral in this story: Don't get too focused on a particular solution to a problem that's been stumping you. Try to think of situations where what you want to accomplish might have already been done. After stopping the blood flow from my forehead, I set out to get some parts: Hopkins Trailer Wiring Kit (#48925) 2xDorman Fully Insulated Disconnects (#85461) You can use the connectors of your choice. I like these because they are fully insulated and will let me undo this mod if I need to. You will also want to get a pair of sockets and 25W automotive bulbs or a pair of resistors to mimic them. Info on the resistors will come later when I get a reply from Teslamaster. But the bulbs will be easy to get and work fine. The socket design doesn't matter. I got a pair of 1157 sockets, but you can also find sockets for 7440/7443 bulbs. And finally, get some quick taps. Either the clamp type found in most autoparts stores or Posi-Taps which are my favorites. You'll also want your usual collection of tools: screwdrivers, wire tool, and an 8mm wrench or pass-thru ratchet. Ok, let's get started: Clean out your trunk. I know you've been saving that half-deflated beachball and old magazines for an impromptu '80s party, but it's time to let go. http://farm2.static.flickr.com/1332/5112505842_f4653ccc92_z.jpg Now there is a plastic piece in the middle of the trunk lp by your legs. In it are three "christmas trees" that hold the front of it in place. http://farm5.static.flickr.com/4133/5111908887_52300a8157_z.jpg Pull these out. I had good luck by using the plastic piece itself. But you do risk damaging it that way. Once they are out, the piece pulls straight up, popping out of four spots along the top; they are white in this picture: http://farm2.static.flickr.com/1423/5112514832_3ef3e648ca_z.jpg With that gone, we need to remove the hooks to either side of the trunk opening: http://farm5.static.flickr.com/4133/5112512632_8b3e91fc3a_z.jpg Turn them 90 degrees towards you: http://farm5.static.flickr.com/4088/5112510134_35e4a12042_z.jpg Then pull back the fuzzy lining and you'll see a tap facing you. http://farm2.static.flickr.com/1432/5111918221_43810a1c60_z.jpg Push it in with a flat bladed screwdriver. The tabs at top and bottom will pass through openings in the bracket that you aligned when you spun the hook. With the hooks out of the way, you can pull back the lining to expose the wiring. (You can remove the assemblies entirely if you want, but I just worked with them in the car.) http://farm2.static.flickr.com/1437/5111920397_17a87359c4_z.jpg The top bulb is the bulb we want to pull its weight. It'll have black (negative) and white (positive) wires coming out of it. http://farm2.static.flickr.com/1221/5111922403_e3b56a438a_z.jpg Snip both wires and cap them with the disconnects. I used males on the harness side and females on the bulb side. You can come up with your own scheme, but keep it simple. Here is the bulb plugged back in after doing this. (This is just to show it. We'll be leaving the bulb disconnected.) http://farm2.static.flickr.com/1391/5112530364_7a05f0e12a_z.jpg Now the car's prepped, let's get to the box. http://farm2.static.flickr.com/1143/5111924657_a39000d80d_z.jpg The scragly wires to the right are car-side, the ribbon to the left if trailer-side. The documentation, while simple, is clear. The box itself is even labeled on the backside. But to cover the wires for those reading along: Car-side: White = Ground Red = Stop Yellow = Left Turn (driver's side) Green = Right Turn (passenger's side) Brown = Park/Tail Trailer-side: White = Ground Yellow = Left Bulb Green = Right Bulb Brown = Marker/Tail If you look at the lengths, you'll see that it was designed to be installed on the left side of the car. Time to prep the wires. We don't have any use for the brown wires. The tails aren't changing. But the other wires do interest us. Time to prep the car-side wires. Get your new bulb socket and if it's a dual filament socket like the one I have, find the bright-side positive so the high-load filament is hooked up. Twist the yellow wire with the positive from the new socket and cap it with a female end. Then cap the negative from the socket with another female end. Do the same with the other socket you bought and the green wire. If you were to plug it in at this point, it'd look like this on the driver's side: http://farm5.static.flickr.com/4091/5111936435_07c10b5180_z.jpg (This picture was taken at the end of assembly, so everything is hooked up, we'll be retuning to this pic later.) The reason why we're installing a new bulb here is because when the brakes are on, the trailer box uses the signal from the turn signal to turn OFF the bulb, not on. So the flasher thinks the bulb is burnt out. It works fine when the signal is on by itself. But will hyperflash if the brakes are on. It's possible, depending on how it's made, that an LED flasher wouldn't have this problem. But I didn't want to waste the money or time to find out. Putting bulbs BACK into the old positions (wiring-wise) was a sure-thing and could be done immediately. Now on to the trailer-side wires. Cut the plug off the end and peel the wires apart from each other like a Twizzler Pull-N-Peel. It should look like this: http://farm5.static.flickr.com/4124/5112527926_45b1c044a3_z.jpg Now cut the trailer-side green wire and trailer-side white wire to the same length as the car-side green (if you need to). Cap them with male ends. Trim the trailer-side yellow to match the car-side yellow. Cap with a male end. Now take a length of wire (preferably white) about as long as the yellow wire you just trimmed and splice it into the trailer-side white wire. Cap this with a male end also. Ok, so we have a loose collection of wires with carious ends and two bulbs, looking like some sort of alien macrophage. We can start hooking everything up. (Continuing in next post) Link to comment Share on other sites More sharing options...
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