QuestionHi Brian, I have a 2005 Buick Lacrosse CXS, with the factory 9 speaker Monsoon System. I want to install a in-dash touch screen gps dvd player preferably with and an i pod connection. i wanted to know if you know of any that would be compatible for my vehicle, without having to rewire anything.
AnswerHi Patrick,
Just about any new head unit that you install into your Lacrosse will need some special adapters to make it work correctly with the factory system.
Like most newer GM vehicles, the Lacrosse's factory radio is integrated with the vehicle's data bus system, and the radio itself controls some vehicle functions. The most noticeable feature that's dependent on the factory radio is the warning chime system--your door chime, headlight reminder, seatbelt warning chime, and so on are all generated by the factory radio and play through the driver's door speaker.
A special adapter interface is available to install a new head unit into your vehicle and retain the stock radio features. The adapter you need is a Metra GMOS-04. This module will work with the vehicle's data bus system and generate the warning chimes. It will also allow you to keep the Onstar system working (if equipped), integrate the new head unit's outputs with the Monsoon amplifier's low-level inputs, and produce an accessory power source for the after-market head unit (another function that's delegated to the data bus in the factory system).
In addition to the GMOS-04 adapter, you'll need a Metra 99-2021 mounting kit, and a 40-GM10 antenna adapter. These parts should work with just about any after-market in-dash DVD/navigation system.
Note that if the factory XM system is equipped, you probably won't be able to retain it with the new head unit; if you want satellite radio, you'll need to purchase an after-market tuner. Also, if your vehicle is equipped with steering wheel controls for audio, they'll also be incompatible with the new head unit unless you purchase another adapter. The exact adapter required will depend on the head unit you choose.
Hope this helps!
Brian
P.S. By the way, the Buick Lacrosse is electrically very similar to a Pontiac Grand Prix. We've been seeing some issues with the Grand Prix, where the OEM instrument cluster malfunctions when the factory head unit is removed. I don't know whether this problem also extends to the Lacrosse. If it does, it might be necessary to keep the stock head unit wired into the system, and relocate it to the trunk.
