04 Tahoe horn wiring - The 1947 - Present Chevrolet & GMC Truck Message Board Network

fauXGT · 07-28-2025, 12:31 AM

After a few days of searching on the old interweb, I am getting conflicting info on what the horn wiring under the dash is. I am wanting to intercept the switch signal under the dash, but am afraid of putting a tone signal from the relay back inside to find it. I don’t want to fry the BCM, or worse the wheel air bag with how some of the schematics show it with the bags. Several versions found on line, but none have the same color wires on plugs. I’ve pulled relay to test from the wheel the ground signal when I think I have the correct wire. Am setting up for switched either factory horn or FD air horn with a tap of the wheel.

Thanks in advance. Chip

**hatzie** · 07-28-2025, 06:41 PM

Try this
https://charm.li/Chevrolet/2004/Taho...al%20Diagrams/

fauXGT · 07-28-2025, 08:53 PM

Well, I’ll be. That color was correct out of the column.
Black/yellow tracer. I just saw your message, and thanks for responding.
I thought by some of the schematics the wheel switch bridged somewhere to the BCM and relay. It converts from black/yellow at the column plug to black at the BCM plug.
Now reassembly tomorrow.

07-28-2025, 12:31 AM	#1
fauXGT Registered User Join Date: May 2021 Location: Spokane, WA / WSS, MT Posts: 268	04 Tahoe horn wiring After a few days of searching on the old interweb, I am getting conflicting info on what the horn wiring under the dash is. I am wanting to intercept the switch signal under the dash, but am afraid of putting a tone signal from the relay back inside to find it. I don’t want to fry the BCM, or worse the wheel air bag with how some of the schematics show it with the bags. Several versions found on line, but none have the same color wires on plugs. I’ve pulled relay to test from the wheel the ground signal when I think I have the correct wire. Am setting up for switched either factory horn or FD air horn with a tap of the wheel. Thanks in advance. Chip __________________ Chip '51 Chevy 3600 5 window C4 Vette front/rear suspension & drive train full Rusto-Mod '92 GMC Sonoma GT VIN #0015 '91 GMC Sonoma GT extended cab 1 of 1

07-28-2025, 06:41 PM	#2
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 5,049	Re: 04 Tahoe horn wiring Try this https://charm.li/Chevrolet/2004/Taho...al%20Diagrams/ __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

07-28-2025, 08:53 PM	#3
fauXGT Registered User Join Date: May 2021 Location: Spokane, WA / WSS, MT Posts: 268	Re: 04 Tahoe horn wiring Well, I’ll be. That color was correct out of the column. Black/yellow tracer. I just saw your message, and thanks for responding. I thought by some of the schematics the wheel switch bridged somewhere to the BCM and relay. It converts from black/yellow at the column plug to black at the BCM plug. Now reassembly tomorrow. Attached Images __________________ Chip '51 Chevy 3600 5 window C4 Vette front/rear suspension & drive train full Rusto-Mod '92 GMC Sonoma GT VIN #0015 '91 GMC Sonoma GT extended cab 1 of 1



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