2002 grand am stereo problem

For starters, I have installed probably about 20 Aftermarket stereos and also several amps and subs, including installing the amp wiring from bay to trunk so I at least have an idea what I'm doing.

I attempted to install an aftermarket Pioneer head unit in my girlfriends 2002 Pontiac Grand Am. After completing the wiring, the head unit would not power on. I am using Scosche GM11 OEM-Aftermarket interface. So I disconnect the 12v accessory (switch) line and connect it to 12V constant and the head unit powers on. For those who don't know, the 12v accessory switch line does not come from the factory harness, it comes from the GM11 interface. So I check voltage across the 12v switch line, and no matter what position the key is in, including out of the ignition, it read about 1.3v.

Obviously I can't leave both the 12v switch and 12v battery connected to constant, the stereo does not shut off. I also have the same GM11 interface in my 2004 Sunfire and it works fine with my aftermarket head unit in that car. So I tried swapping the GM11 interfaces back and forth between cars, and they both worked in my car, and neither would provide the 12v switch on the Grand Am.

Google has failed me. But led me here for hopefully some insight.

 did you check your fuses? not a visual but with a DMM? if not that is where i would start....... let us know what happens.

You can always run a wire from the fuse panel. Find a fuse that is "hot when ignition on" and tie into that. Dont forget to increase the fuse size by 10 amps.

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The Only Stupid Question, is the one Un-asked

Never increase the size of a fuse as this creates a fire hazard. Check that the purple wire in the factory radio harness is in the same position for both vehicles. This is the data line that controls everything. If that is OK, plug in the module in the Grand AM but don't plug in the radio. Use a digital meter set to measure DC voltage and measure across the BLACK/ white wire in cavity A12 and the orange wire in cavity B1. You should get 12 volts. Turn the ignition ON and check the voltage again and on the ignition output wire of the module. You should see 12 volts again on both. Turn the igntion OFF and plug in the radio. Test the 2 wires again for voltage to see if you are getting 12 volts. You may have a bad module or a power/ground problem in the Grand AM.

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sparky

boogeyman wrote:

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did you check your fuses? not a visual but with a DMM? if not that is where i would start....... let us know what happens.

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I did a visual but did not use a multimeter. I'll do this first.

sparkie wrote:

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Never increase the size of a fuse as this creates a fire hazard. Check that the purple wire in the factory radio harness is in the same position for both vehicles. This is the data line that controls everything. If that is OK, plug in the module in the Grand AM but don't plug in the radio. Use a digital meter set to measure DC voltage and measure across the BLACK/ white wire in cavity A12 and the orange wire in cavity B1. You should get 12 volts. Turn the ignition ON and check the voltage again and on the ignition output wire of the module. You should see 12 volts again on both. Turn the igntion OFF and plug in the radio. Test the 2 wires again for voltage to see if you are getting 12 volts. You may have a bad module or a power/ground problem in the Grand AM.

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I'll try this if the former doesn't help.

bbullers wrote:

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You can always run a wire from the fuse panel. Find a fuse that is "hot when ignition on" and tie into that. Dont forget to increase the fuse size by 10 amps.

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After reading from other GA owners, this appears to be my last resort, but then I may not bother as it's a moderately cheap stereo and a fairly low end model.

I have an 04 Grand Am GT1....Thats what I had to do, and I have a $600.00 Eclipse deck

Also, I've never had a problem with the fuses, and have been doing this for years now. It's up to you, and how you want to do it.

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The Only Stupid Question, is the one Un-asked

hey guys,

there is a simple answer for this problem, theres no need for checking fuses or rewiring.

the interface works by decoding the factory data system. not all data systems are the same!!!  especially GM.

on the sunfire the GM11 works just fine this is because the gm 11 contains the encoding for gm's 11 bit data code. What the problem here is that the Grand am does not work of the same 11 bit data code. the data system in the grand am is much faster. all you need is the correct interface which you can get from best buy (GM09SR) or any other shop. walmart also carries one that should work as well (gm2000). the interface gives you your acc turn on plus all your factory chimes and will not throw any engine or diagnostic codes.

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";P