Tech: Quad beam headlight mod

[treepete]

JK, this is a bit pedantic but, what type of relay are we talking about here? I stopped in at the store and the dude said there were plenty to choose from, and what kind I needed. Just thought would aask if there was a specific type or PN for this function.

sorry to be all dumb.:confused2:

 

[JKmotorsports]

JK, this is a bit pedantic but, what type of relay are we talking about here? I stopped in at the store and the dude said there were plenty to choose from, and what kind I needed. Just thought would aask if there was a specific type or PN for this function.

sorry to be all dumb.:confused2:

Ask for a typical SPDT automotive relay, such as those used in some aftermarket driving/fog light systems. These will have 5 contacts labeled 85, 86, 87, 87a, and 30. You might have better luck going to your local stereo/alarm shop, as these are always used , especially in alarm installations. They'll know exactly which one to give you; the type used in aftermarket automotive integration are basically industry standard.

 

[bigpov]

JK, I have a dumb question for ya. When I'm hooking up the relay to the wires behind the headlights, do I cut the wires or just put in one of those plastic pieces that lets me tap into them? Sorry for the dumb question, I just want to be sure before I go hacking into wires. Thanks for all your help. This forum is awesome. Lots of people willing to help out.

 

[bigpov]

"Well, it took a while but I finally found the info I needed. As I suspected, the yellow wire at the back of the low-beam bulb is connected to the popular yellow wire under the electrical center. The yellow on the low beam and the purple on the high beam are alternately switched to ground by the dimmer switch. If the yellow wire could be permanently grounded, the low beam would stay on when the high beam is switched on. The grounded-yellow-wire-under-the-electrical-center trick accomplishes this, but...

The easy all-on mod FOR A 2002 is:

1. Remove the two pins and pull the headlight assembly forward a couple of inches.
2. Use about a 1' length of approx #16 wire to tie into the yellow wire going to the low beam bulb.
3. Ground the other end of the 1' wire. There is a handy fender bolt a few inches back from the headlight.
4. Re-install the headlight assembly.

Done. Took less than 5 minutes on my truck and works fine.

DO NOT ATTEMPT THIS WITH AN '03+

No, seriously, DONT !!"



This came from a guy over at dieselplace.com, thanks newfydad. Sounds a little easier and quicker, definitely cheaper than a relay ($13 at napa). I've seen this floating around a few times, but nothing right a the headlight other than with the mod with the relay. What do you guys think? Is this just another way to accomplish the same thing? Or is one way better than the other?

 

[JKmotorsports]

JK, I have a dumb question for ya. When I'm hooking up the relay to the wires behind the headlights, do I cut the wires or just put in one of those plastic pieces that lets me tap into them? Sorry for the dumb question, I just want to be sure before I go hacking into wires. Thanks for all your help. This forum is awesome. Lots of people willing to help out.

You don't have to cut the wires, just strip back some of the insulation and splice into it. The t-taps you are referring to are unreliable, especially in vehicles because of constant vibration. I always suggest soldering connections. I can't tell you the number of times I've had to diagnose electrical systems for problems and traced it down to a loose t-tap connector.

 

[JKmotorsports]

:

....2. Use about a 1' length of approx #16 wire ...

... What do you guys think? Is this just another way to accomplish the same thing? Or is one way better than the other?

Sounds like another great way to perform this mod. Cool. But I would use larger gauge wire, at least 14 or 12, especially if you have your lights on for long periods of time.
Thanks for sharing the info:thumbsup:

 

[bigpov]

You don't have to cut the wires, just strip back some of the insulation and splice into it. The t-taps you are referring to are unreliable, especially in vehicles because of constant vibration. I always suggest soldering connections. I can't tell you the number of times I've had to diagnose electrical systems for problems and traced it down to a loose t-tap connector.

Thanks for the heads up. I didn't realize the t-taps were such a problem. I'll just go ahead and take them back then. Along with the relay. Man, this mod is getting cheaper and cheaper. Hopefully that tip you gave me will turn my fog lights too. I'll let you guys know. Thanks again.

 

[bigpov]

Well, I finally took 5 minutes and did it. I used about 12" of 14 gauge wire and grounded the yellow wire on the low beams, right behind the headlight. I tapped into it and grounded it right inside the hood on the bracket/brace that goes across just above the battery. Worked like a champ.

JK, I tried to jumper my fog lights at the BCM but it didn't work. Can you PM me and walk me through what would be the best way to set up a manual switch inside. I really just need to know where to tap into to make sure the fog lights don't stay on after the tahoe is turned off, not that my wife would do that. lol And where to plug that power into in the fuse box. Thanks for all your help.

 

[bigpov]

Bump

 

[JKmotorsports]

bigpov, did you use a diode? If so, try installing it the opposite way if you haven't already. Let me know what happens and I'll get back with you on another way to make this happen if this doesn't work.

 

[bigpov]

I'll crawl under there and give that a shot. I think something is wrong with the fog light wiring running into my cab, that's why I'm trying to figure out a way to do it out under the hood and just run an after market switch. I'll give the diode under the dash one more shot though. Thanks again.

 

[jpmaniac87]

Sweet mod, just did it today in minutes. Preciate the write up!

 

[jpmaniac87]

hey, if i plan on getting HID in the future, would i have to remove this mod??

 

[JKmotorsports]

hey, if i plan on getting HID in the future, would i have to remove this mod??

No. This won't affect any type of bulb or system you install. I have HIDs on both my highs and lows with this mod.

 

[river rat]

Diode

I have a 2006 Tahoe and would love to make this mod. I looked at the RS website for diodes, and there are many flavors. JK--any further description of which one to get for the job?? In the description, it says to locate connector C2, but then describes which wires to connect the diode to. What significance is connector C2 to this process?

I made this mod to my 01 and it helped tremendously!

 

[JKmotorsports]

I have a 2006 Tahoe and would love to make this mod. I looked at the RS website for diodes, and there are many flavors. JK--any further description of which one to get for the job?? In the description, it says to locate connector C2, but then describes which wires to connect the diode to. What significance is connector C2 to this process?

I made this mod to my 01 and it helped tremendously!

You can use a 1-3amp diode. The wires I listed are located in connector C2.

 

[bzbatl]

I need to do this mod this weekend. When I get home from gigs late I night, I just barely pull back on the turn signal switch, and it activates the high beams without shutting off the lows.

Ghetto quad mod.

 

[Slammed]

Can I do this on my 99??

 

[bahollis]

Will this work on an 04'? I tried stripping back a little wire on the yellow from the low beam and grounding it, but it did not work. I tried every piece of metal & bolt I could reach with an 18" piece of wire.

Not that you'd do it permanently, but could you not touch the end of the wire to the negative post of the battery to test it out for sure? I don't know, that's why I'm asking.

I'd like to do this mod if possible.

BH

 

[JKmotorsports]

Will this work on an 04'? I tried stripping back a little wire on the yellow from the low beam and grounding it, but it did not work. I tried every piece of metal & bolt I could reach with an 18" piece of wire.

Not that you'd do it permanently, but could you not touch the end of the wire to the negative post of the battery to test it out for sure? I don't know, that's why I'm asking.

I'd like to do this mod if possible.

BH

Try it this way:
03-up models
You will need to locate the BCM, which is underneath the driver's side dash.
Locate connector C2, which will be gray.
Locate pin B1, which is a black wire with a white stripe. Verify with a digital multimeter that this wire sees ground when you turn the high beams on. Connect the cathode end of the diode (the end with the band around the diode) to this wire.
Next locate pin A4, which is a pink wire with a white stripe. Verify that this wire has ground when the low beams turn on. Connect the other end of the diode to this wire.
That's it. Now turn on your headlights and switch on your high beams and make sure all four are on.