99 Grand Am - Changed alternator, now radio does not work

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  #1  
Old 07-03-05, 02:41 PM
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99 Grand Am - Changed alternator, now radio does not work

Today while visiting my daughter and son-in-law stationed at the Naval Air Station in Pensacola, I helped him change the alternator on his 99 Pontiac Grand Am. All went well, until we tried the radio. It will not come on. Of course, we had the negative battery cable disconnected while we changed the alternator. My first assumption that it was the theft deterrent system built into the radio. I read the manual, but it just acts like it is not getting any power. It does not display "LOC" as the owners manual suggested it would after loss of power. No display or sound of any sort. There is a slight glow near the CD slot when I turn the lights on, but other than that no signs of any life or power. I checked the fuses. Both labeled for the radio are good.

Any help you can provide will be greatly appreciated.
 
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  #2  
Old 07-03-05, 03:24 PM
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Sounds as if there is a class 2 data problem. I suggest you take the car to the dealer to have the DTC's pulled. Does this car have a sunroof?
 
  #3  
Old 07-03-05, 03:47 PM
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What is a class 2 data problem and what is a DTC?
 
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Old 07-03-05, 03:55 PM
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A DTC is a diagnostic trouble code. They set in whatever module(s) detects a problem. All the modules in the car communicate with each other via class 2 serial data circuit. When there is an interuption in this circuit, the affected modules, or items that run off the modules, will be inoperable, as long as the problem is current.
 
  #5  
Old 07-03-05, 04:03 PM
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But before hand, you may want to check the radio fuses.
 
  #6  
Old 07-03-05, 04:43 PM
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Fuses are OK

I noted in my original posting that I already checked the fuses and they are OK. I don't want to go to a dealer. They will charge me an arm and a leg. If it is just a DTC, can it be cleared with the device which reads them and then the radio will operate?
 
  #7  
Old 07-03-05, 06:30 PM
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I am unfamiliar with these aftermarket code readers. But from what I understand, they do not read any codes other than powertrain codes. If there is indeed a problem with the class 2 serial data circuit, the radio will continue to not work until the problem is fixed or the interuption is no longer present. Clearing the code will not do any good. Just for sh!ts and giggles, inspect the fuse block on the left side of the instrument panel. These cars had a few problems with moisture intrusion in that fuse block. Look for any corrosion at the terminals of the fuse block. There will be a few purple wires leading from the fuse block(these are class 2 wires). This is about all the advice I can offer, since I am not sure what the exact problem is, and I have no DTC's to refer to a diagnostic chart with. If you do happen to retreive any DTC's, make sure to check all the modules and post them up so we can walk you through the diagnosis.
 
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