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Old 07-20-2017, 07:24 PM   #1
88lowrider
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Join Date: Mar 2008
Location: Eugene Oregon
Posts: 107
Wirning for all 4 headlights for High beams

I did a search but not finding anything in this section.
My 1988 as 4 lights. Two come on for low beams, you punch on the high beams and the lows go off and the two high beams come on.

I would like it to once the light are on low, punch on High beams and have all four come on. I did have the heavy duty harness that I purchased from LMC Truck.

Any treads I should go look at ? Still searching but I am really crap at how to search the treads.

Thanks.
Helmar
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Old 07-20-2017, 08:17 PM   #2
88lowrider
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Location: Eugene Oregon
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Re: Wirning for all 4 headlights for High beams

Quote:
Originally Posted by 88lowrider View Post
I did a search but not finding anything in this section.
My 1988 as 4 lights. Two come on for low beams, you punch on the high beams and the lows go off and the two high beams come on.

I would like it to once the light are on low, punch on High beams and have all four come on. I did have the heavy duty harness that I purchased from LMC Truck.

Any treads I should go look at ? Still searching but I am really crap at how to search the treads.

Thanks.
Helmar
Well, when all else fails, Google it.
I found all kinds of kits to do this and of course, things get complicated.
So anyway, found one youtube video that shows just one jumper wire up under the dash or down by the steering column but no mention about using different lights. I think he had the standard old sealed beams. I am converting mine over to the once I can change the bulbs.
I Do have a 4 amp relay and I also have a 20 amp and 30 amp blade style plug in breaker. The kind when they over heat, the open, cool off, close back up.
I think I will keep looking for the mods were you can capture the wires as they are at the head lights, make the mod right in front, mount the relay and breaker with power going direct to the battery....
I will let you know what I come up with.

Quick update.
I forgot to add I got from LMC Trucks, the wiring harness that is there 36-3582 which converts my Sealed beams to, shoot....The type that you can just change the bulbs like in all the newer cars.
It comes with two 25amp relays so all the light switch power does now is trigger the relays that control the lights. The harness goes direct to the battery with a fuse in it.

I just have to figure out how to get both headlights on when on High beams. Been reading too much and now confused with using Diodes now too??

I can upload the wiring diagram that came with the harness if someone can help me. I will go get a picture of it now and upload it soon.

Helmar

Last edited by 88lowrider; 07-20-2017 at 10:42 PM. Reason: Forgot something.
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Old 07-20-2017, 11:03 PM   #3
88lowrider
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Re: Wirning for all 4 headlights for High beams

I hope these pictures show up good enough.
Here is hoping.
Helmar
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Old 08-03-2017, 01:48 PM   #4
87Skier
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Re: Wirning for all 4 headlights for High beams

I just did this on my 96. Wiring is pretty much the same on the older stuff.

I can upload a schematic if you need it, just let me know.
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Old 08-03-2017, 02:26 PM   #5
88lowrider
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Re: Wirning for all 4 headlights for High beams

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Originally Posted by 87Skier View Post
I just did this on my 96. Wiring is pretty much the same on the older stuff.

I can upload a schematic if you need it, just let me know.
Yes, that would be Great.
Like I said, I have that wiring loom I got from LMC came with two 25 amp relays to take the load off the light switch on the steering column.
I have not installed it as I can't figure out how to get both lights on when on high beam.

I did get the headlights and park lights that converted me from the old sealed beams over to the newer, replace the bulbs when you want brighter lights.
http://www.lmctruck.com/icatalog/cd/full.aspx?Page=65

Not to be whining but I used to be pretty ok figuring these things out but age and health got me. I still enjoy tinkering :-)

Helmar
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Old 08-03-2017, 02:27 PM   #6
88lowrider
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Re: Wirning for all 4 headlights for High beams

I just looked to see were you were located. I just came though your town twice last Monday :-)
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Old 08-03-2017, 03:33 PM   #7
87Skier
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Re: Wirning for all 4 headlights for High beams

First you will need to cut the wiring to the headlights. It is easiest to cut it close to the battery. Not sure how your truck is wired but I've seen where the headlights are in a "T" configuration on the drivers side and I've seen where they ran 2 wires to the drivers side and 1 wire to the passenger side. Don't cut them too short if you intend to reuse the headlight connectors.

The low beam and high beam wires from the truck need to run into either 85 or 86 of the relay. The other connector (85/86) needs to be connected directly to ground. A diode needs to be connected from the high beam signal to the low beam signal with the band closest to the low beam signal.

Either 87 or 30 on the relays need to be connected through a fuse to the battery. Then the last terminal goes to their respective low beam or high beam headlight.

I recommend soldering and heatshrinking all connections except the relay and headlight terminals.

There are other ways of doing this. This way runs all the headlights off the battery instead of using the wiring from the cab of the truck reducing a lot of load. This requires the fewest number of relays and fuses, but does require the factory wiring to be completely cut. If the wiring isn't completely cut, the diode could attempt to feed the headlights and fail.

I recommend using:
20 A fuses for each pair of headlights
Standard 30 A 12 VDC relays
Insulated terminals for the relays (or wiring harness for them)
1 A diode (1N4401 or similar)

Remember to test stuff as you go along. If you install the diode in reverse polarity the high beams will stay on with the low beams and will shut off when you turn the high beams on.
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Old 08-03-2017, 07:23 PM   #8
88lowrider
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Join Date: Mar 2008
Location: Eugene Oregon
Posts: 107
Re: Wirning for all 4 headlights for High beams

Quote:
Originally Posted by 87Skier View Post
First you will need to cut the wiring to the headlights. It is easiest to cut it close to the battery. Not sure how your truck is wired but I've seen where the headlights are in a "T" configuration on the drivers side and I've seen where they ran 2 wires to the drivers side and 1 wire to the passenger side. Don't cut them too short if you intend to reuse the headlight connectors.

The low beam and high beam wires from the truck need to run into either 85 or 86 of the relay. The other connector (85/86) needs to be connected directly to ground. A diode needs to be connected from the high beam signal to the low beam signal with the band closest to the low beam signal.

Either 87 or 30 on the relays need to be connected through a fuse to the battery. Then the last terminal goes to their respective low beam or high beam headlight.

I recommend soldering and heatshrinking all connections except the relay and headlight terminals.

There are other ways of doing this. This way runs all the headlights off the battery instead of using the wiring from the cab of the truck reducing a lot of load. This requires the fewest number of relays and fuses, but does require the factory wiring to be completely cut. If the wiring isn't completely cut, the diode could attempt to feed the headlights and fail.

I recommend using:
20 A fuses for each pair of headlights
Standard 30 A 12 VDC relays
Insulated terminals for the relays (or wiring harness for them)
1 A diode (1N4401 or similar)

Remember to test stuff as you go along. If you install the diode in reverse polarity the high beams will stay on with the low beams and will shut off when you turn the high beams on.
After looking at your circuit design, I can see how it works..
The relays they gave me are some other foreign ones that do not have numbers, But, I found the pin out for them. It has two on the wiring loom that I got from LMC so looking at that loom and your wiring diagram circuit and add the diodes.
This loom has heavier wire and plugs in back towards the firewall. Its more complicated as it also feeds the turn signals and running lights.
Your wiring diagram is a solid heavy duty design and I like it.

Oh, the only change I would have done is not fuses but the breakers.

I will use some of my Marine 16ga wiring and use your design on my 76 Dodge Van.. It came with the big round bulbs but I use a tube grill and Monty Carlo head light buckets.
Low beams comes on, the goes off for the High beams..
I want them Both on when on High.

Thank you Very much for the Help
Helmar

Last edited by 88lowrider; 08-03-2017 at 07:35 PM.
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