Onstar will work with aftermarket units it cost about $100 more for the Onstar module, not all stereo shops carry it have to check to see who doesIm not sure if this was covered or not but does the onstar features work with all aftermarket headunits.
I use the GPS function once in a while and was wondering if the information still shows up
great info! i am running a 4 channel amp to power my front and rears, and getting a mono amp to run the subs. With of course and aftermarket in-dash.FYI, You can change the speakers in vehicles with the OEM amp, but you will lose power because of the difference in impedence from the OEM speakers 1.3ohm to aftermarket ones that are 4 ohms. In other words the amp won't have to work as hard to drive the aftermarket speakers and they will not be as loud as the factory ones. This in turn should make aftermarket speakers not sound very good with the OEM amplifier, but they would still work. I haven't checked the speakers on mine to verify this is a 1.3 ohm speaker. If you want better sound then you should replace both the amplifier and speakers possibly even the headunit. Or what I did on my Bu was to just add a small sub for the bass so now I am able to turn the bass down on the factory headunit making the factory speakers sound better.
The factory amplifier is located at the rear passenger corner in the trunk between the wheelwell and tail lights.
My 08 displays the info through the headunit.... does that mean I loose the capability to view said info if I replace the factory HU with an aftermarket one??The DIC information is displayed in the main instrument cluster, and the controls for it are on the steering wheel. However, that doesn't guarantee that the headunit has nothing to do with it. In the past there have been many functions handled through factory headunits that didn't appear to until the headunit was pulled. I would expect that this isn't the case here. However, warning chimes (door open, lights on, seatbelt unfastened, etc.) and OnStar are probably still integrated with the headunit, regardless.
There are usually aftermarket modules available to handle these issues when you put in a replacement headunit though.