Why won’t my 2003 GMC Sierra aftermarket radio turn on?

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May 14, 2025 at 6:13 pm #1394 Reply
Dave
2003 GMC Sierra Z71. Bought a new aftermarket radio for the truck and wired a plug to it to plug into the stock harness and I have no power to turn it on. Matched all the wires correctly, but all I have is the constant from the yellow and one that flashes when the key is on or off. But if I plug my stock stereo in, it turns on. I’ve never had an issue installing a radio until now, and I’ve done many, but it’s driving me crazy, so I’m turning to you all for advice. TIA
May 14, 2025 at 6:42 pm #1395 Reply
Mike
The one that’s flashes with the key is on is the + side of the CAN network. It won’t carry enough current to turn on the head unit.

How the original worked is battery constant power with a ground of course and the wire that flashes is the “network wake up signal” so the original will wake up when the network is active.

The easiest thing to do on this style is to tie into the keyed power at the HVAC controls directly beneath it.
May 14, 2025 at 6:42 pm #1396 Reply
Chris
GM does NOT supply a keyed power to the radio, make your own or use a module.
May 14, 2025 at 6:42 pm #1397 Reply
Steve
If you bought the Plug to install to the OEM Harness, the Radio will have the Wiring Diagram Right on it or in the Owners/Install manual.
May 14, 2025 at 6:43 pm #1398 Reply
John
Recheck all your wires….
My guess is your diagrams do not match
If they do radio junk…
Can you put power to the radio and it works
Just main 12v power and ground.
Hows the ground on the “new” radio
May 14, 2025 at 6:43 pm #1399 Reply
Dale
There is no ignition source behind the radio. It’s canbus. You need to find your own ignition source under the dash near the ignition harness behind the key.
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Why won’t my 2003 GMC Sierra aftermarket radio turn on?

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