Theiobot
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(Photo) Light Bar & Pillar Lights Fuse Piggyback Suggestions
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Vladimir2306
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My personal opinion is that the installation is very unsuccessful. There will be a strong glare from the hood, and the driver will be self-blinded. As for the connection, I have an LED Bar connected to the high beam via a relay. The power itself is taken from the battery, and the relay turns on the power for the high beam. Plus there is a deactivation button in the cabin. It turns out that I can turn on Far with LedBar together or without LedBar, but I can’t turn on Ledbar separately
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I wired mine in a similar fashion but a bit more complex. I have a auto/manual switch and an on/off switch for each light. I can supply the on/off switch from the high beam (from lighting control module under the dash) or from auto/manual switch (supplied directly from the battery). The 2 sources are combined before the on/off switch via a pair of diodes, such that one source can't feed the other. The on/off switch then feeds a relay under hood to power the cubes or light bar.
With the first switch off (auto), and the second switch on, the LEDs only come on with the high beams. My default configuration is Off (Auto) / On (driving pattern cubes with amber covers) / Off (spot / driving light bar). If I'm in a populated area but still want high beams, I'll disable the cubes and if I'm really in the middle of nowhere, I'll enable the light bar. In auto, dimming the headlights shuts off any auxiliary lights which may be on.
Manual mode allows the lights to work regardless of the high beams are on or off, or if the truck is running or not. The 2 scenarios where I use manual mode is to illuminate an area in front of the truck with the truck off (use the truck as a utility light), or to use the cubes without the high beams (amber driving pattern is sometimes helpful in fog, rain or snow).
Assuming those are more than just accent lights, I'll suggest powering them from a relay (power direct from the battery with an inline fuse) and triggering from your high beams (these will be very irritating to other drivers, based on mounting height, regardless of pattern). If you're also looking for a circuit power when the truck is running, it appears 37, 38, 40, 44, 46 and 47 are only powered when the ignition is on and 85, 86, 87, 88, 89, 90, 91 and 92 may only be powered when the engine is running. Interior fuses 26 (and maybe 27) appear to be related to retained accessory power (IIRC, stays live for 10 minutes after ignition is turned off). Be careful tapping these circuits as they mostly relate to your trucks critical systems. I would tap via an add-a-fuse, only use a very small fuse to trigger a relay and ensure the relay included a fly-back diode.
You can download basic schematics for your truck from GM's upfitter website. They aren't complete but offer a lot of insight into the power and lighting systems.
Jeff
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Theiobot
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lol, my installation is unsuccessful. .. Its never blinded me. I've got 1,000+ miles of real off roading through death valley, Mojave desert and etc with no issues. Is there some bounce back off the hood, yes, but the light emitted is far more benefitial for sight than the issue. Plus its an easy fix to be installed this weekend of black vinyl to absorb some of the bounce back. As far as high beam relay idea i like that as would be nice to have all turn on with high beam but for now all is controlled individually or as pairs via a controller.
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Theiobot
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Would you happen to have a build spec for this, I want manual control and auto for high beams and the reverse lights/chase lights i want to add. Would love to know how you wired it in or what diodes you used.
I didn't sketch the circuit, but I'll try to post a few details in the next week or so.
The basics include picking up the triggers from the lighting control module (above the drivers right foot), ORing them with switched +12V from the battery (off = auto, on = manual) to feed "enable" switches (off/on) for each relay/light. Diodes are used in the OR junction to prevent back feeding the LCM in manual mode and to prevent the LCM from powering anything unintentionally (such as highbeams also turning on reverse lights). IMO, flyback diodes are a must when controlling relays from any factory wiring (prevent voltage spikes when relay is turned off). My diodes are just generic Amazon diodes I had leftover from another project.
Jeff
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