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- Dodge Ram 2nd Gen How to Replace Headlamp Relay
Step by step instructions for the do-it-yourself repairs.
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Headlamp Relay Write-up
#1
08-12-2008, 08:38 PM
Nice writeup. This should be put in the DIY section. To me it's much better than my LMC harness. Well, actually I can probably modify it to do this if it works with the foglights unlike it. I just was at a loss when it didn't work as the wires seemed backwards of the factory ones when testing them with a meter so I wasn't sure which wire was what.
#2
08-13-2008, 01:50 AM
This should not touch your fog lights at all, as I'm assuming they go through the headlamp switch in the cab like the headlights do.
You may also want to hook up a third relay for the fogs. My aftermarket fogs kit draws its power straight from the battery, to its own fuse, and then to an aftermarket switch before going to the lights. I even went and bought a nice heavy duty switch (its bolted down between the park brake release and the hood release) so that I won't have any problems with melting switches.
You may also want to hook up a third relay for the fogs. My aftermarket fogs kit draws its power straight from the battery, to its own fuse, and then to an aftermarket switch before going to the lights. I even went and bought a nice heavy duty switch (its bolted down between the park brake release and the hood release) so that I won't have any problems with melting switches.
Last edited by jasonw; 08-13-2008 at 03:10 AM.
#3
08-13-2008, 09:59 AM
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01-11-2010, 03:17 PM
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Headlamp Relay Write-up
for
1999-2001 Dodge Rams w/o Sport Package
for
1999-2001 Dodge Rams w/o Sport Package
Version 1.2
Preamble: I just wanted to thank the various DodgeForum.com members who contributed to headlight relay write-ups. They were just never clear enough for me, so I decided to give it a shot of my own.
Disclaimer: By following this write-up, you assume all responsibilities for any consequences (negative or positive) that may come from it.
Materials Needed:
·Two 30A automotive relays
·Two single automotive fuse holders
·Two new 9004 type headlight harnesses (9007 headlight harnesses will also work, same unit)
·12 gauge wire, 14 gauge wire, and 16 gauge wire
·Wire cutter
·Wire stripper
·Soldering gun and solder wire (not absolutely necessary, but would give you better connections)
·Electrical tape
Important Terms:
·“Attach” – When I use this word, I mean to twist together, solder, crimp, or use whatever means you deem fit to attach wires together. ALWAYS use electrical tape over top of whatever connection you make.
Directions:
1) First, find a good place to mount the relays inside the engine bay. I chose to do it right next to the driver’s side headlamp, close to the battery.
2) Look at the bottom of the relay. You should have four or five terminals, numbered 30, 85, 86, and 87. You may also have an 87A, which is just another 87 connection. I chose to use Directed Electronics, Inc.’s 8626 relay assembly, which already had the wires attached to a plug that snaps onto the relay, and a fuse already attached to terminal #30. However, for the purpose of this write-up, I will pretend that my relays did not have wires attached already.
3) Let’s start with the low beam relay. Take one of the relays, and position it in the general area where you will be bolting it up, but do not bolt it yet unless you already have wires coming from the terminals.
4) Take the driver’s side headlamp bulb and harness out of the headlight assembly. Remove the bulb (don’t touch the glass with bare fingers) and cut the center wire. That is the low beam wire.
5) Run a length of 16 gauge wire (however much you require) from the wires going to the old harness to the relay (I labeled this wire “Red”). Attach the center wire that originally went to the old harness (should be red or red with yellow stripe, if you have a 2001 model year) to relay post #86. This is the relay activation wire.
6) Take one of the new headlight harnesses, and attach the center wire to relay terminal #87 using whatever length of 14 gauge wire you require. (I labeled this wire “Brown”.)
7) Take the wire on the left side of the new harness (should be black in color), and using whatever length of 14 gauge wire you require, ground it to a good point on the vehicle’s frame.
8) On the old harness, cut the left wire (should be purple in color for 2001 model year). Run whatever length of 16 gauge wire you require, and attach that wire to relay terminal #85 (I labeled this wire “Black”). This, obviously, is the relay’s ground wire.
9) Attach a length of 12 gauge wire to the battery positive terminal. Attach two lengths of 14 gauge wire (one for each relay) to the end of this 12 gauge wire.
i) Using one of the 14 gauge wires (I labeled this wire “Yellow”), attach a fuse holder, but do not put a fuse in it yet. Attach the other end of the fuse holder, still using 14 gauge wire, to relay terminal #30.
10) Run a length of 14 gauge wire from either terminal #87A, if you have one, or instead attach it to relay terminal #87, over to the passenger side headlamp (there should be two wires total coming from terminal #87 if you don't have a #87A).
11) Withdraw the headlamp bulb/harness assembly from the headlamp housing. Remove the bulb. Zip tie this old harness out of the way, hidden if you can, it will no longer be used. You can, of course, clip it off completely instead if you choose.
12) Take a new harness, and attach its center wire to the #87/#87A wire you just ran.
13) Ground the new harness’s left wire (should be black in color) to a good point on the vehicle’s frame using 14 gauge wire.
14) Put the bulbs into the new headlamp harnesses, and insert them into the housings.
15) Insert a fuse into the fuse holder. My relays came with 10A fuses, but Dodge uses 15A for each headlamp in the stock wiring, and that’s what I decided to use instead. I wouldn’t go any higher than 20A.
16) If you haven’t done so already, bolt the relay to its final resting place.
17) Repeat this procedure with a second relay for high beams, with a few important changes:
i) Instead of attaching the old harness center wire to #86 (steps 4 and 5), use the right wire (should be a solid purple in color for 2001 model year). That’s the high beam wire.
ii) Instead of attaching the new harnesses’ center wire to relay terminals #87/#87A, attach their right wires. It’s the only unattached wire left on the new harnesses.
iii) Ignore steps 7, 9 (but not 9i), and 13. Note: In step 8, you will connect both relays’ black ground wires (terminal #85) to that same wire.
iv) In step 9i, use the second length of 14 gauge wire coming from the original 12 gauge wire.
18) Test time. Turn the headlight switch to “on”. You may hear the relay make a “click” type noise, this is normal, and the headlights should now be on. Check both low beams and high beams. If not, recheck your wiring and your connections. At the end of this write-up, I’ve included a summary wiring diagram to help with troubleshooting.
Any questions or comments, or if you want a copy of this write-up in Microsoft Word (or some other) format, email them to Jason.Westerberg@gmail.com.
------------------------------------------------------
Version History:
8/12/08- Version 1.0 completed, including "relay" graphic and "plug assembly" graphic.
10/17/08- Version 1.1 completed.
*Incorrect wiring instructions corrected and a few minor additions made.
*Graphics corrected and improved.
10/19/08- Version 1.2 completed.
*Graphics replaced with single, better "diagram" graphic.
Is there a version of this for earlier models like my 1997 that has two bulbs per side?
#7
01-11-2010, 03:38 PM
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01-11-2010, 08:54 PM
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No. Find the hot wire for each bulb. The hot wires would go to pin 30 or 87 on the relay. Then connect 30 or 87 (which ever one you did not use for the hot lead going to the bulb) and connect to the battery. In other words, cut your hot wire (12v) far enough back from the connector to be of use. Connect the bulb side to 30 or 87 the switch side to 85 or 86. Then add a ground to 85 or 86 that is not being used. Connect the ground wire from the light switch to the empty 85/86 pin. Connect new ground to the bulb and your good to go.
2 wire bulb is hot/ground. The 3 wires for low beams sounds like you have daytime running lamps? Turn the lights on, grab a meter and find the hot wire(s). If you do have daytime running lights, I'd think about leaving that connection alone. If when low are on you have 2 hot and one ground might as well hook both hots to 30 or 87.
Confused?
87/30 is the "switch" part of the relay. 85/86 is the coil that activates/deactivates the switch. I'd also suggest you get single pole single throw (SPST) relays to limit any additional confusion.
2 wire bulb is hot/ground. The 3 wires for low beams sounds like you have daytime running lamps? Turn the lights on, grab a meter and find the hot wire(s). If you do have daytime running lights, I'd think about leaving that connection alone. If when low are on you have 2 hot and one ground might as well hook both hots to 30 or 87.
Confused?
87/30 is the "switch" part of the relay. 85/86 is the coil that activates/deactivates the switch. I'd also suggest you get single pole single throw (SPST) relays to limit any additional confusion.
