Emergency beacon wiring found!

[Offcamber]

I post this since I had trouble finding the information....

 

After searching the web and even asking a GM tech I now I finally found where the wires are for the factory emergency beacon switch. Most of my troubles came from inaccurate or out of date info that there is a "harness" inside the headliner, that is not correct at least on my 2016 2500. There are two wires located in the ceiling console. They are just blunt cut wires....a ground (black) and a blue green wire. There is also a 4 wire plug not connected that goes to the switch on the console. All you need to do is run two wires from the the console to your light and connect the plug to the switch. I ran the wires across the front of the headliner, down the pillar, behind the fuse panel and out to the engine compartment through the large grommet by the master cylinder and then under the cab and back to the headache rack where the light is. I will need to run one more positive lead from the light to a momentary switch in the cab so I can change the flash pattern.

 

fairly easy job once you know what your looking for. I'll post some pics when its a 100% done.

 

Here is the ground wire..sorry for the crappy pic...

 

[Webhair]

Good to know - thank you for posting.

[Andy Seibel]

Now can we confirm if those wires are only present in vehicles with the "plow prep" package, or are they in every truck?

[newdude]

Now can we confirm if those wires are only present in vehicles with the "plow prep" package, or are they in every truck?

 

Plow prep only (which on 1/2 ton trucks means regular cab only).

[Offcamber]

My understanding is that it uses the same circuit as the sunroof on models equipped with one....can't have plow package and sunroof or remote link either.

[trx680]

emergency beacon???

 

what is this used for?

[Cowpie]

Obviously it was primarily meant for installing yellow flashing lights on top for commercial snow plowing, construction work, etc. But I suppose it could be used for just about any light setup that doesn't blow the fuse.

[Offcamber]

It has a 30amp fuse so you could put a lot on it.

 

Sent from my XT1650 using Tapatalk

[Chebbyfan]

Could this switch be used to run an LED lightbar in the front bumper hole?

[Offcamber]

Could this switch be used to run an LED lightbar in the front bumper hole?

Yes absolutely...easy install if you are moderately mechanically inclinded.

[GMC4Zee]

I used the power to install aftermarket homelink on my old truck. With the plow prep package it comes with the switch already so having it control any auxiliary lights is possible.

[Chazd]

Here is a pic of where the wires were on my 2017 C2500 Service Body truck. You can see the bare wire ends. I think the only practical way to get to them is removing the whole console, maybe you can be more clever.

[Anthony Amato]

The GM Upfitter UI Bulliten #123b (Roof Beacon (TRW) Switch Wiring Location/Access) contains the circuit diagram in it also and confirms that you need to remove the console to access the wires. 

 

[Mitch47]

Just got a Silverado 2500HD Duramax and am trying to wire a cab top, magnetic red light for fire and rescue. This forum helped me find the wiring, but is there an existing hole through the roof, say under the marker light, to get the wire from the light to the switch connection?  Thanks.

 

mitch47

[2016HD]

So only on Plow prep trucks? Or all trucks?? Did not see a 100% answer.  And if its there on all trucks without homelink and Sunroof?  what and where are you adding the switch? Thanks!