I have had this problem twice, and my Nav was installed at the factory.

 

We do not have Navigation installed on our Vehicle. It is worth noting that this all started up after having the vehicle in for a recall. Something to do with the key fob's and dead car battery. Has anyone else noticed this problem after getting that recall taken care of?

 

ZX
I installed my nav after I purchased my tahoe. Both times the unit shut down I had to restart my car 3 times before the unit would power up. No turn signal sound, and the had unit was blank with no power.

 

Do you have the GM Lockpick?

I have only seen this problem with the Lockpick installed.

 

no lock pick, currently. I tryed one but it froze my nav and would never work right.

 

I spoke with Onstar today and they said that the vehicle diag has nothing to do with this problem and to take it to the dealer. I had them run a diag twice and they said everything was fine. No problems with my Tahoe when they ran the diag. They did say they were having problems with XM, and had problems in the past with XM, and that might be the problem.Who Knows. I hope to find out on Tues when my Tahoe goes in for service.

 

I have somewhat of the same problem. Instead of the nav system getting messed up, when I change radio stations the turn signal sound turns off. It also messes up the timing of the signal, changing stations makes the signal blink faster.

 

I just had this problem on my Avalanche this morning. Dead nav systems, no turn sounds +Park sensor is turned off permanently and cannot switch back on.
Since I live in Europe, where Onstar is not in function, we can rule out this as the cause (the vehicle is not equipped with Onstar).

However, my nav system is purchased off eBay and installed afterwards, and I also have a Peripheral PXDP3 iPod interface installed.
Has anybody come close to a solution?

 

Did you check the park sensor switch below the HVAC controls? Sometimes it can accidentally get switched off by something in console.

I had one instance where all sounds died. After work that day everything was back to normal and never did it again.

 

Yes, Ichecked that. The P-sensor is not my concern, it is the fact that the nav system dies periodically. Turn signal sound offand P-sensor off are just side effects of the audio system not functioning.
This morning everything was back to normal (will not de-install my iPod interface yet)

Has anyone tried to measure the power in on the head unit, when these problems occur? Do we know if the problem is inside the head unit or in the wires/fuse box?