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Old 12-08-2005, 12:30 AM   #1
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Location: Benbrook, TX
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headlight relay install

I did this to my trucks after reading this:
Brighter Head Lights @

1 Read the artical
2 Parts list 2 bosch relays, spade connecters, wire, and inline fuse.
3 Look at wiring sheet
4 Decide that you can do this
5 Start by finding the 14LG and the 18LT wire on the back of the left headlamp.
6 Disconnect the (-Neg) battery cable. Mount the relays to the core support above the horn. You may have to make room for them.
7 Follow the 14LG wire towards the fuseblock. Mark it. This is the one to cut.
8 Follow the 18LT wire towards the fuseblock. Mark it 1st. Cut this one also.
9 Do the wiring:
cut 18LT (or low beam) and run the wire from the fuseblock to Terminal 86 on the relay.
run the other end and that comes from the headlamp plug to Terminal 87 on the relay.
cut 14LG (or hi beam) and run the wire from the fuse block to the Terminal 86 on the 2nd relay. run the other end to Terminal 87 of the 2nd relay.
10 Terminal 85 goes to ground.
11 Run a heavy wire (12ga.) from + Battery Post to Terminal 30 of both relays. Just run it through the stock wiring across the radiator. Add a inline fuse on this one.
12 make sure every thing is connected, secure wires,
replace (- battery cable )
13 Enjoy Brighter Head Lights
69 swb stepside, rebuild and upgrade in progress

Last edited by matt67350; 01-24-2009 at 09:24 PM.
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Old 03-14-2006, 04:53 PM   #2
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Re: headlight relay install

I'm going to put a new Painless Wiring Harness in my truck. Will I still have to do this relay thing so my Tri_Bar headlites will work like they are supposed to.?
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Old 04-30-2006, 09:40 PM   #3
that's right!
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Join Date: Mar 2004
Location: Topsham, ME, USA
Posts: 101
Re: headlight relay install

Will this stop my headlight dimming when I stop at a stoplight? Man is that annoying.
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Old 05-29-2006, 12:13 PM   #4
Longhorn Man
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Location: Hilliard Ohio
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Re: headlight relay install

Already gone, your new lights will work, but they'll work better with this mod. Also, this mod reduces the amount of amps going through the harness, into the cab, through the headlight switch, through the dimmer switch... so they all have less of a load. It increases the amps at the bulb, sop they burn way brighter.
jugadro, this won't stop the dimming all together... you should look into an upgrade on your alt to stop that.
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