Help with 2019 Silverado HLF install

[63Medic03]

I need help with a HLF install in my 2019 Chevy Silverado (newer style)Custom Trail Boss. I got a Sound Off ETHFSS-SP-ISO which is what I was told works on my vehicle. Everything is wired up right to the headlights and power and grounds. Every time I apply power to the trigger wire it trips the fuse in the power wire. I’ve now install two of these units and had the same issue with each of them. Yes, Im about 90% sure it’s installed properly. The high beams still work when installed. Attached is the wiring diagram. Also, I added in these extensions, pictured below and tapped into with the flasher. This way I didn’t cut into the factor wiring harnesses. I can’t figure it out; any help or previous experience would be appreciated.

 

[carguy411]

2 things. Sometimes those extensions are Wired reverse
It sure if you double checked the wires before plugging in to factory harness

The other which is most important When I was doing an install on a 2020 I was told specifically from whelen not to flash the headlights because they are controlled through bcm and can potentially fry the computer
And I believe doing a 2019 in past it was same issue. Just a thought

 

[63Medic03]

Thanks for the reply. I’ll check the extensions.

My Silverado is the version with halogen headlights and I’ve seen other installs where they did put this model HLF in.
Thanks for the help!
joe

 

[EVT]

4 wire isolated HLF will not allow power to be backfed to BCM. Whelens flashers are not as advanced as SOS and thus don't work in the same vehicles.

 

[billforbush]

I have an SOS iso in a 2018 2500HD and it works great.