4 Hi Headlight Mod

[oohunter04oo]

You only need 2 if using the method I've posted before.

One for lows, one for highs.

You also get the short run full 12v from the batteries.

What is this method?

 

[phule]

Tap into the yellow wire coming out of the headlight switch in the dash. Run that wire out to pin 85 on your relay. Ground pin 86. Put 12v on pin 30. Run pin 87 to your lowbeams.

Done.

Now you can do whatever you want with your high beams as your low beams are now independent of your high beams. As a side bonus, if your multifunction switch ever messes up your low beams will still come on.

Lastly, you've now got a built in 4 hi mod. Your highs can be switched on and off without effecting the lows. Thats really good for hid's as they don't like power interruptions at all....not at all.

30a relay minimum, 40a preferred. A double pin 87 relay is preferred as you can run a dedicated wire to each headlight instead of jamming two wires into on blade connector. It also splits the load across two contactor's inside the relay instead of one.

I like 10 gauge stranded wire, but that's overkill for most people's setup. 12 gauge is more than enough. 14 gauge is getting pretty small for headlight harness IMHO...

I think this post?

Adam

 

[oohunter04oo]

I think this post?

Adam

Thanks!

Great White, what is the yellow wire for?

 

[Old77]

Good news=the previous did the 4 Hi mod for me (only had my truck about 6 weeks)

Bad news=there seems to be a bad connection somewhere. Driving through the snow tonight with the brights on the low beams would sporadically go off and then come back. If it'd ever warm up I'd take a look at it but I guess that'll happen in a couple of weeks. Anyone have guesses where the issue could be?

 

[95C1500]

Good news=the previous did the 4 Hi mod for me (only had my truck about 6 weeks)

Bad news=there seems to be a bad connection somewhere. Driving through the snow tonight with the brights on the low beams would sporadically go off and then come back. If it'd ever warm up I'd take a look at it but I guess that'll happen in a couple of weeks. Anyone have guesses where the issue could be?

did they solder or use crimp connectors? maybe one isn't crimped right and the truck bumping around causes it to lose connection...

 

[Old77]

That's a good possibility. I'll have to take a look at that and is kinda what I was thinking as well. Right now it's about 5* outside but hopefully I can take a close look this weekend

 

[95C1500]

That's a good possibility. I'll have to take a look at that and is kinda what I was thinking as well. Right now it's about 5* outside but hopefully I can take a close look this weekend

while you're under there, do it properly IMO. That is, if the PO did a crappy job in the first place.

 

[great white]

Thanks!

Great White, what is the yellow wire for?

Its the dash switch trigger wire for low beams. You turn it in to the trigger wire for the relay instead of the high current wire feeding the headlights.

The high beams I just use one of the feeds to trigger another relay to feed straight bat voltage. I have hid high beams, but it works for halogens just as well.

 

[oohunter04oo]

Its the dash switch trigger wire for low beams. You turn it in to the trigger wire for the relay instead of the high current wire feeding the headlights.

The high beams I just use one of the feeds to trigger another relay to feed straight bat voltage. I have hid high beams, but it works for halogens just as well.

Ok, so is this Correct?

Lowbeam relay
30 - 12V
86 - Ground
85 - Yellow wire from headlight switch
87 - Wire to Low beam


Highbeam Relay
30 - 12V
86 - Ground
85 - Highbeam signal
87 - to Highbeam


so will this work to get me full 12V to lows and highs, and be 4hi?

 

[great white]

Ok, so is this Correct?

Lowbeam relay
30 - 12V
86 - Ground
85 - Yellow wire from headlight switch
87 - Wire to Low beam


Highbeam Relay
30 - 12V
86 - Ground
85 - Highbeam signal
87 - to Highbeam


so will this work to get me full 12V to lows and highs, and be 4hi?

Give me a day or so and I'll toss up a diagram but yes; that looks right at first glance.

Meter your wiring behind the headlight switch. I believe it was the yellow wire, but it was a while ago when i did mine.....