Harness for 4-headlights, 4-on low, 4-on high

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=144147
Printed Date: May 04, 2024 at 6:15 PM

Topic: Harness for 4-headlights, 4-on low, 4-on high

Posted By: unfortunately
Subject: Harness for 4-headlights, 4-on low, 4-on high
Date Posted: February 11, 2018 at 2:51 PM

Hello,

I have a 1989 Toyota LandCruiser, the model with 4 headlights. It's a 24v model (yes, even the headlights), but I don't think that that will affect the design of the harness. Toyota headlights operate on a switched-ground system. I'd like to revers that to switched power. Current configuration is H1 highs and H4 lows. I'd like to build a harness that allows for all 4 lights to be on during low-beam operation and all 4 lights to be on during high beam operation. I have two Bosch 5-pin relays, and a couple of old harnesses from other projects that I can hack up and repurpose here. However, I'm having trouble wrapping my head around how to configure the harness and relays to achieve what I'm after. Any chance anyone has an idea of how to do this?

Cheers

Replies:

Posted By: unfortunately
Date Posted: February 11, 2018 at 5:16 PM

This is how i've got it imagined. Does that look right?

The lights being installed are LED and can operate in a 9v-32v range. Simplicity and cleanliness of wiring dictates that I'll run them from the balanced 12v fuse block instead of 24v off the high side battery.

Posted By: unfortunately
Date Posted: February 11, 2018 at 5:18 PM

I based this off of the diagram here: https://www.the12volt.com/relays/relaydiagram8.html

Posted By: unfortunately
Date Posted: February 11, 2018 at 6:16 PM

Updated for cleanliness & efficiency.

Posted By: the12volt
Date Posted: February 12, 2018 at 10:18 AM

Your diagram looks good to me for switching 12V+ to each light during high and low.

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Posted By: unfortunately
Date Posted: February 13, 2018 at 10:55 AM

Thanks for having a look. Now to build the harness and wire it up. I'm not super confident in my electrical skills, I appreciate the extra set of eyes on my diagram.

Posted By: unfortunately
Date Posted: February 21, 2018 at 9:54 PM

Thanks again, I got the harness built and my new headlights working as expected. Cheers!

Posted By: the12volt
Date Posted: February 22, 2018 at 8:11 AM

You're welcome. Happy to hear you have it working.

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