Heavy Duty Headlight Harness and 4 Hi

[GMRedline]

I'll be installing my 4 HI HD harness from TRS soon. I'm just waiting for my new headlights to show up.

 

[88GMCtruck]

That doesn't inlcude 4 HI. Correct?

Yeah, it has 2 relays, not all 3

You don't need 3 Relays to run 4-hi. One relay runs low, one runs high. All you need it a diode to continue to trigger the lowbeam relay when the highbeam is on. Using a 3rd relay just makes the lowbeam relay mechanically move to the off position and a 3rd relay trigger.

 

[montessadam88]

Can you draw up a schematic for this including the high and low conversion. Im planing on making this but want to include where the high and low beams are on at the same time. Please and thanks.

 

[GMRedline]

Can you draw up a schematic for this including the high and low conversion. Im planing on making this but want to include where the high and low beams are on at the same time. Please and thanks.

The first diagram at the top of this thread is correct when using 3 relays.

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You can make a 4HI HD harness with only two relays as mentioned above. It would require installing a 1 way 12v diode between the Green 86 wire and the Orange 86 wire from this diagram. The 1 way diode would need to be installed in the orientation that allows the 12v current to travel from the Green 86 wire to the Orange 86 wire.

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[montessadam88]

Is there a certain one i should look for? Im new to diodes. And im not finding much online unless i order from china.

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will these work

 

[GMRedline]

Honestly, I don't know. I went looking yesterday figuring I could find a nice cheap pre-wired one some where but came up short. Maybe that is why people use relays? It only cost a couple more bucks to get a cheap relay.

I just went through this myself. Thinking I could "build" a nice Heavy Duty 4HI harness myself. For nice quality HD components it was going to cost me at least $50-$60 to do it myself. And that doesn't include my time. I could build a cheaper Standard Duty 4HI Harness for $30 or $40 but I wanted something HD.

Instead I bought the 9005 and 9006 HD Relay Harness from TRS.

http://www.theretrofitsource.com/co...9005-hb3-relay-wire-harness.html#.VhfNLflVhBc

http://www.theretrofitsource.com/co...low-beam-relay-wire-harness.html#.VhfOf_lVhBc

And their GM Correctional Splitter

http://www.theretrofitsource.com/co...beam-correctional-splitters.html#.VhfP1vlVhBc

So I got $80 into it but it is high quality and plug and play. The setup I got from TRS is over kill. Basically each headlight will run off it's own relay. The nice thing about the harness is that I can use it to power HID ballasts if I ever want to switch to HIDs.

Barron used to sell his HD 4HI Harness for $100.

http://www.gmt400.com/forum/showthread.php?5004-88-98-Heavy-Duty-Headlight-Harness-Kit-(NEW)

I asked TRS about making a HD 4 High Harness with 3 Relays designed like the ones Barron used to make and they said they would! But I would have to order 100 of them...

 

[montessadam88]

Ill ask the company selling the diodes. I got all my wiring from work. I got the relays cheap and found ceramic connectors they are headlight wireing extenders so ill cut them and solder me a nice set

 

[hiredgun8]

That diode will not do it. That one limits you to 12v. The first time you start your truck it will blow it.
Look for a diode in the 8-10 amp range and 50V or higher. I use T10A40L's. And remember current flows toward the stripe. And soldering them in is always better than any crimp connector.

 

[GMRedline]

Honestly, I don't know. I went looking yesterday figuring I could find a nice cheap pre-wired one some where but came up short. Maybe that is why people use relays? It only cost a couple more bucks to get a cheap relay.

I just went through this myself. Thinking I could "build" a nice Heavy Duty 4HI harness myself. For nice quality HD components it was going to cost me at least $50-$60 to do it myself. And that doesn't include my time. I could build a cheaper Standard Duty 4HI Harness for $30 or $40 but I wanted something HD.

Instead I bought the 9005 and 9006 HD Relay Harness from TRS.

http://www.theretrofitsource.com/co...9005-hb3-relay-wire-harness.html#.VhfNLflVhBc

http://www.theretrofitsource.com/co...low-beam-relay-wire-harness.html#.VhfOf_lVhBc

And their GM Correctional Splitter

http://www.theretrofitsource.com/co...beam-correctional-splitters.html#.VhfP1vlVhBc

For those who might be interested...

The Correctional Splitter that TRS sent me has the diode installed the wrong way. So when the Low Beams where on, it would also turn on the high beams. I called them on Friday and they are going to send me a new one. But I got impatient and wanted to finish the project this weekend.

So I cut out the diode from their splitter and installed it into the factory harness on the drivers side. Then I decided to modify the two separate HD harness (total of 4 relays) to make them into one (2 relay) harness. I knew the 4 Relay setup was over kill for my setup. Also, the Morimoto Relays that come from TRS are really nice so I will use the 2 extra for something else like E fans.

I wish I would have taken more pictures.

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If I had to do it all over again, I would order 2 HD Relay Harnesses and make my custom one. Then buy a one way diode separate. It costs about $65 and I have 2 very nice Motimoto Relays left over.

 

[1994]

Im interested in doing this since my low beams are absolute trash light output. Is OP still active so I can message him about walking me through making a harness?