QuestionQUESTION: Hey Brian,
I got rid of my factory radio and now im trying to install my savant mhd4720i double din indash tv, i brought the proper wiring harness (gm factory harness with onstar) the radio turns on and it has sound but its low. so i try to see if it was the speakers giving the problem and when i put the factory radio back in the sound is excellent. can u help me with this problem cause i ready to bash this car with a hammer.
ANSWER: Hi Rico,
Can you tell me exactly which model of interface adapter you're using, and whether your Monte Carlo is originally equipped with a Bose audio system?
I'm familiar with several different GM interface adapters. They tend to connect in different ways. Some of them are designed to plug into your head unit's RCA pre-amp outputs; these are generally used with factory-amplified systems (like GM Bose systems). Other interface adapters connect to the head unit's speaker outputs; these are used with factory audio systems that don't have factory amplifiers, or use high-level inputs like a Monsoon audio system. At least one adapter includes RCA plugs, but directs you to cut off the plugs and connect directly to the new head unit's speaker outputs if you don't have a Bose system.
If your vehicle's factory audio system is a Bose package, then you should be using an interface adapter that plugs into the new head unit's RCA outputs. In this case, there's usually a gain control somewhere on the adapter that lets you increase the input level. You may just need to turn up the gain.
On the other hand, if your car does not have the Bose system, then the adapter shouldn't be connected to the RCA pre-outs. It should be connected to the speaker level outputs. If your adapter doesn't give you that option, then you may be using the wrong adapter.
Hope this helps!
Brian
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QUESTION: well brian im using the pac os bose wiring harness. i look in the trunk to see what kind of amp was there and it doesnt have a name on it, its just a silver box so i dont think it a bose system but the interface say bose and non bose. i seen the volume adjust button on it and try to turn the level up from the harness and i think it just control the volume of onstar. can u tell me if im using the wrong one or not?
AnswerRico,
It looks to me like you have the wrong one. PAC makes two modules listed for your car: The OS-2 and the OS-2 Bose. I haven't used them personally, but from looking over the instruction manual for each, it doesn't look like they're interchangeable.
If you don't see the Bose logo on the front speaker grilles or the face of the factory head unit, you don't have a Bose audio system. Some Monte Carlo's have factory amplifiers that aren't Bose. In this case, the non-Bose OS-2 module is the right choice.
If you're stuck with the OS-2 Bose module, you can probably make it work by connecting your head unit's speaker outputs directly to the speaker wires in the harness, instead of connecting the speakers through the OS-2 Bose unit. (This is somewhat similar to the "option 2" wiring diagram in the instruction manual, although an after-market amp won't be present). To do this, however, you'd need to install an extra speaker for the Onstar audio.
Hope this helps!
Brian
