2007, 2008 & 2009 Nav Upgrade - Simple Questions

JeepTherapy · December 17, 2008

Ok, so please no flames. I have spent several hours (!) searching the archives & have found many posts on the new body style nav units & upgrades, but for the life of me I can't find the answers to these questions.

Background:

I used to have a 2005 GMC Extended cab Sierra (non-Bose) and successfully put in a factory nav unit using the information I found on this forum. I did all the work myself, so I'm familiar with the ins & outs.

Currently:

I have purchased a new (to me) 2007 GMC Sierra Crew cab. It's an SLE (I hate leather & consoles) - so there's no Bose. (Actually the way I like it - I'm not a fan of Bose stuff, but that's another thread....

Questions:

1. Do the '07 & up Nav decks have power amps in them, or are they like the older style in that they are only made to work with a offboard Bose amp & therefore contain only a pre-amp?

2. Do the '07 & up trucks still use the headunit to generate the warning chimes?

3. Assuming the new nav decks don't have power amps in them, has anybody confirmed their pre-amps are standard line-level jobs (that I can splice into an offboard power amp) or is it also like the older ones in that they use a proprietary level signal that doesn't mate well to offboard amps?

That's it! I think with that & all the other threads I've found, I have enough information.

Thanks in advance.

DofD · December 17, 2008

As far as I've heard and read all the GMT900 nav decks are amplified with an external Bose amp. The chimes I believe are generated in the head unit still. I also believe the pre-amp outs of the head unit are line level.

JeepTherapy · December 18, 2008

As far as I've heard and read all the GMT900 nav decks are amplified with an external Bose amp. The chimes I believe are generated in the head unit still. I also believe the pre-amp outs of the head unit are line level.

So it sounds pretty much like a Nav upgrade to a non-Bose truck involves all the same tricks as before, only with new peripheral interfaces to deal with the new lan?

Bish · December 18, 2008

Head unit on my 08 isn't even a preamp. It outputs constant low volume (with speaker connected to it) with no volume control or fader control. I believe it is also only two channel output. The stock nav unit is useless without the Bose amp. It can, however, be significantly improved while keeping the factory nav and bose amp.