crazy stereo!

[99tahoeinwv]

i have a 99 tahoe that i bought off my wifes aunt. whenever it feels like it the sound from the stereo goes out. power is still to the unit, the lights are on, the "st" flashes like the signal is still there, but no sound. then at some point and time a week or more later, or maybe next day, it will come back on. sometimes it comes back on at full blast and scares the crap out of me and then it might go back out and comes back eventually. i have pulled the head unit out and even replaced it last year, but it did the same thing with the other unit. any thoughts of where to start?

 

[yates ™]

Stock stereo? Bose?

I assume it has a factory amp which is malfunctioning.

 

[SunlitComet]

intermittent main power line loss but not ignition feed loss. or perhaps amplifier ic issues which just happen to hit you twice. you got details on type of radio and if you the factory amp and how many speakers you got. 2dr or 4dr. if you have the luxury one i think all the outputs go thru the amps so it may be that. the base setup has only a few outputs from a separate amp but the radio has speaker outputs to so the type is important to know for diagnosis.

 

[99tahoeinwv]

sorry, yeah its the factory delco radio, 4 door tahoe, speakers on each door and the two in the back by the liftgate. when it works, it works great, but it seems like something is shorting something out at times, just seems odd it still has power, but no sound. is the amp built in the head unit like most others? or is it separate?

 

[SunlitComet]

do your have a radio control panel farther to the rear of vehicle like in the back of center console.

 

[99tahoeinwv]

no, just the head unit in the dash. it also has the single cd player that is separate and below the head unit

 

[EMF Audio]

sorry, yeah its the factory delco radio, 4 door tahoe, speakers on each door and the two in the back by the liftgate. when it works, it works great, but it seems like something is shorting something out at times, just seems odd it still has power, but no sound. is the amp built in the head unit like most others? or is it separate?

It sounds like a blown speaker shutting the HU outputs off. Next time it isn't working, try disconnecting 1 speaker at a time and see if it comes back.

 

[SunlitComet]

so you know for sure that if one output is shorted some how the whole amplifier section shuts down? then will later come back after the fault is removed but at a higher volume?

---------- Post added at 04:59 PM ---------- Previous post was at 04:41 PM ----------

no, just the head unit in the dash. it also has the single cd player that is separate and below the head unit

well that pretty much eliminates a factory external amp as a cause which leads me to believe you have the redio setup in the diagram. if the failure is present suddenly like with key on engine off remove the radio without turning of the power to radio by key. probe the wire for voltage on constant and switched feeds and measure resistance of each speaker and report back.
Radio/Audio System Schematics (Base): RADIO and RADIO BATT Fuses, Radio, Speakers, G200

 

[99tahoeinwv]

Thanks for the input emf i had a guy one day say the same thing. Are the door panles on these things tough to get off? In theory as soon as i disconnect it will the system turn right on if thats the case?

 

[EMF Audio]

so you know for sure that if one output is shorted some how the whole amplifier section shuts down? then will later come back after the fault is removed but at a higher volume?

It's a VERY common problem. The surround on the speakers get damaged, the coil sits sideways in the gap and shorts on the motor. That dead shorts the outputs and goes into protect. Hitting a bump or anything of that nature can take that very slight connection away.

Thanks for the input emf i had a guy one day say the same thing. Are the door panles on these things tough to get off? In theory as soon as i disconnect it will the system turn right on if thats the case?

They are pretty easy to take off, a door panel removal tool would help get it started if you don't have real strong finger tips. It's been quite a while since I took one off, but IIRC there is a real possibility you may break the white pins that hold it to the door. Be careful putting the panel back on, line it up with the hole before pounding it in.