I just purchased a 2003 Yukon Denali. Radio quit working. Display shows station being played and back entrainment ear plugs work but nothing coming out of speakers. Carried to Chevy dealer, they charged me 80 bucks and said I need an amp, $900.They did give me a wiring diagram of the plugs (2) back of radio. Went and order amp from a salvage yard. Before it arrived radio started working again. Went out again. I notice same time radio is out the key in ignition chime does not work. When radio works so does chime. The wiring diaphragm they gave me shows a mute wire but my plug does not have this. The speaker code is UQ7 ,Y91. I have power on the orange wire that is battery voltage but I don't have anything on the orange wire on A1 which says it is a serial data wire. Does this wire suppose to have voltage? I suspect something is going on in the steering column. Does anyone have a wiring diagram of wiring in column? Any help would be greatly appreciated.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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If there was a problem with the steering column, you would have other issues. entertainment wiring\connectors do not go to the column at all.
The serial data wire should not have voltage on it. You may see a varying voltage around 2-3volts but nothing above 5volts.
The chimes are operated by the amplifier, so when the audio goes out for the radio, the chimes are not able to work either.
A common area for problems on these trucks are under the center console. Give the console a smack on one side or the other to see if you can get it to act up. You may have to remove the console to find a pinched wire under it.

A bad amplifier is not unheard of. If you find no pinched wires, I would assume that the amp is bad.

 

Thanks so much

 

I have ohmed all the speaker wires out and show no grounds. Radio is playing thru back entainment center ear plugs but no sound from speakers. Speakers come on once and a while. I have 7 wires on the B side of the 24 pin plug that goes to amp. Looking from side of plug where wires plug in I have drk blue pin 3, bare wire pin 6, lt green pin 7, tan pin 8, drk grn pine 9, orn pin 10, grn/blk pin 11, drk grn pin 12. Does anyone know where these wires go?

 

Audio Amplifier C1 (UQ7 w/Y91)

<TABLE border=1 width="95%"><TBODY><TR><TH vAlign=center colSpan=4 align=middle>



</TH></TR><TR><TH vAlign=center colSpan=2 align=middle>Connector Part Information
</TH><TH vAlign=center colSpan=2 align=left><TABLE border=0><TBODY><TR><TD vAlign=top>• </TD><TD vAlign=top>12110088</TD></TR></TBODY></TABLE>

</TH></TR><TR><TH vAlign=bottom align=middle>Pin

</TH><TH vAlign=bottom align=middle>Wire Color

</TH><TH vAlign=bottom align=middle>Circuit No.

</TH><TH vAlign=bottom align=middle>Function

</TH></TR><TR><TD vAlign=center align=middle>A1

</TD><TD vAlign=center align=middle>WHT

</TD><TD vAlign=center align=middle>1854

</TD><TD vAlign=center align=left>Right Rear Twiddler Speaker Output (+)

</TD></TR><TR><TD vAlign=center align=middle>A2

</TD><TD vAlign=center align=middle>YEL

</TD><TD vAlign=center align=middle>1949

</TD><TD vAlign=center>Right Rear Twiddler Speaker Output (-)

</TD></TR><TR><TD vAlign=center align=middle>A3

</TD><TD vAlign=center align=middle>BRN

</TD><TD vAlign=center align=middle>199

</TD><TD vAlign=center>Left Rear Speaker Output (+)

</TD></TR><TR><TD vAlign=center align=middle>A4

</TD><TD vAlign=center align=middle>YEL

</TD><TD vAlign=center align=middle>116

</TD><TD vAlign=center>Left Rear Speaker Output (-)

</TD></TR><TR><TD vAlign=center align=middle>A5

</TD><TD vAlign=center align=middle>TAN

</TD><TD vAlign=center align=middle>201

</TD><TD vAlign=center>Left Front Speaker Output (+)

</TD></TR><TR><TD vAlign=center align=middle>A6

</TD><TD vAlign=center align=middle>GRY

</TD><TD vAlign=center align=middle>118

</TD><TD vAlign=center>Left Front Speaker Output (-)

</TD></TR><TR><TD vAlign=center align=middle>A7

</TD><TD vAlign=center align=middle>DK BLU

</TD><TD vAlign=center align=middle>46

</TD><TD vAlign=center align=left>Right Rear Speaker Output (+)

</TD></TR><TR><TD vAlign=center align=middle>A8

</TD><TD vAlign=center align=middle>LT BLU

</TD><TD vAlign=center align=middle>115

</TD><TD vAlign=center>Right Rear Speaker Output (-)

</TD></TR><TR><TD vAlign=center align=middle>A9

</TD><TD vAlign=center align=middle>LT GRN

</TD><TD vAlign=center align=middle>200

</TD><TD vAlign=center>Right Front Speaker Output (+)

</TD></TR><TR><TD vAlign=center align=middle>A10

</TD><TD vAlign=center align=middle>DK GRN

</TD><TD vAlign=center align=middle>117

</TD><TD vAlign=center>Right Front Speaker Output (-)

</TD></TR><TR><TD vAlign=center align=middle>A11-A12

</TD><TD vAlign=center align=middle>--

</TD><TD vAlign=center align=middle>--

</TD><TD vAlign=center align=left>Not Used

</TD></TR><TR><TD vAlign=center align=middle>B1

</TD><TD vAlign=center align=middle>DK GRN

</TD><TD vAlign=center align=middle>1488

</TD><TD vAlign=center>Noise Reduction Microphone Supply Voltage

</TD></TR><TR><TD vAlign=center align=middle>B2

</TD><TD vAlign=center align=middle>LT GRN/BLK

</TD><TD vAlign=center align=middle>1354

</TD><TD vAlign=center>Drain Wire

</TD></TR><TR><TD vAlign=center align=middle>B3

</TD><TD vAlign=center align=middle>ORN/BLK

</TD><TD vAlign=center align=middle>1546

</TD><TD vAlign=center>Right Front Low Level Audio Signal (-)

</TD></TR><TR><TD vAlign=center align=middle>B4

</TD><TD vAlign=center align=middle>DK GRN

</TD><TD vAlign=center align=middle>1947

</TD><TD vAlign=center>Left Front Low Level Audio Signal (-)

</TD></TR><TR><TD vAlign=center align=middle>B5

</TD><TD vAlign=center align=middle>TAN

</TD><TD vAlign=center align=middle>511

</TD><TD vAlign=center>Left Front Low Level Audio Signal (+)

</TD></TR><TR><TD vAlign=center align=middle>B6

</TD><TD vAlign=center align=middle>LT GRN

</TD><TD vAlign=center align=middle>512

</TD><TD vAlign=center>Right Front Low Level Audio Signal (+)

</TD></TR><TR><TD vAlign=center align=middle>B7

</TD><TD vAlign=center align=middle>BARE

</TD><TD vAlign=center align=middle>2011

</TD><TD vAlign=center>Drain Wire

</TD></TR><TR><TD vAlign=center align=middle>B8-B9

</TD><TD vAlign=center align=middle>--

</TD><TD vAlign=center align=middle>--

</TD><TD vAlign=center>Not Used

</TD></TR><TR><TD vAlign=center align=middle>B10

</TD><TD vAlign=center align=middle>DK BLU

</TD><TD vAlign=center align=middle>2272

</TD><TD vAlign=center>Amplifier Class 2 Serial Data

</TD></TR><TR><TD vAlign=center align=middle>B11-B12

</TD><TD vAlign=center align=middle>--

</TD><TD vAlign=center align=middle>--

</TD><TD vAlign=center align=left>Not Used

</TD></TR></TBODY></TABLE>

 

Audio Amplifier C2 (UQ7 w/Y91)

<TABLE border=1 width="95%"><TBODY><TR><TH vAlign=center colSpan=4 align=middle>

</TH></TR><TR><TH vAlign=center colSpan=2 align=middle>Connector Part Information
</TH><TH vAlign=center colSpan=2 align=left>

<TABLE border=0><TBODY><TR><TD vAlign=top> • </TD><TD vAlign=top>12110626</TD></TR></TBODY></TABLE>
<TABLE border=0><TBODY><TR><TD vAlign=top> • </TD><TD vAlign=top>8-Way F Metri-Pack 280 Series (GRY)</TD></TR></TBODY></TABLE>

</TH></TR><TR><TH vAlign=bottom align=middle>Pin
</TH><TH vAlign=bottom align=middle>Wire Color
</TH><TH vAlign=bottom align=middle>Circuit No.
</TH><TH vAlign=bottom align=middle>Function
</TH></TR><TR><TD vAlign=center align=middle>A
</TD><TD vAlign=center align=middle>BLK/WHT
</TD><TD vAlign=center align=middle>1851
</TD><TD vAlign=center align=left>Ground
</TD></TR><TR><TD vAlign=center align=middle>B
</TD><TD vAlign=center align=middle>DK GRN
</TD><TD vAlign=center align=middle>1795
</TD><TD vAlign=center>Right Subwoofer Speaker Output (+)
</TD></TR><TR><TD vAlign=center align=middle>C
</TD><TD vAlign=center align=middle>RED
</TD><TD vAlign=center align=middle>1858
</TD><TD vAlign=center>Left Rear Twiddler Speaker Output (+)
</TD></TR><TR><TD vAlign=center align=middle>D
</TD><TD vAlign=center align=middle>LT GRN/BLK
</TD><TD vAlign=center align=middle>1794
</TD><TD vAlign=center>Left Subwoofer Speaker Output (-)
</TD></TR><TR><TD vAlign=center align=middle>E
</TD><TD vAlign=center align=middle>DK BLU/
WHT
</TD><TD vAlign=center align=middle>346
</TD><TD vAlign=center>Left Subwoofer Speaker Output (+)
</TD></TR><TR><TD vAlign=center align=middle>F
</TD><TD vAlign=center align=middle>PPL
</TD><TD vAlign=center align=middle>1958
</TD><TD vAlign=center>Left Rear Twiddler Speaker Output (-)
</TD></TR><TR><TD vAlign=center align=middle>G
</TD><TD vAlign=center align=middle>LT BLU/BLK
</TD><TD vAlign=center align=middle>315
</TD><TD vAlign=center>Right Subwoofer Speaker Output (-)
</TD></TR><TR><TD vAlign=center align=middle>H
</TD><TD vAlign=center align=middle>ORN
</TD><TD vAlign=center align=middle>3740
</TD><TD vAlign=center>Battery Positive Voltage
</TD></TR></TBODY></TABLE>

 

The sterring column has volumn, seek, phone that controls radio. Could one of these be shorted ? Does these come thru the serial data wire?
thanks,

 

if they were shorted none of the buttons on the radio would work. it would not cause a loss of audio