I have an 07 Saturn Ion 2 that I installed an X920BT in. I bought the GMOS LAN 06 wiring harness to retain onstar functionality. I installed the head unit in my car, attaching the parking break wire (light green) to the ground, and not bothering to attach the speed sense wire at all. I also didn't bother to attach the harness with all the RCA connections to the head unit, as I wasn't going to use any of them.

Everything seemed fine for a few days, but then yesterday morning for no reason at all the car alarm started going off. I turned the car alarm off with the key fob, and drove to work. On my way to work the car was repeatedly trying to lock the car doors. Last night the alarm kept going off again and the dome light kept turning on. I went as far as to remove everything I had done in the car and put the stock radio back in place, still hasn't stopped the alarm from going off, the doors from trying to lock themselves or the dome light from turning itself on.

Any thoughts? I'm going to take it in to a GM dealer later today, but thought I'd throw this out there for all of you to chew on...

is it the factory alarm? if the problem still persist after the factory radio was reinstalled, then the radio wasn't causing the problem, however something may have been damaged during the install, maybe the GMOS was defective and did some thing to one of the cars computers since they all communicate with each other through the data bus

i dont really know, just throwing out ideals.

It is the factory alarm. I'm thinking maybe the GMOS was bad. I still have to take apart the console by the driverside feet and check the BCM connections. It was suggested that they may be loose...

i wouldn't expect the bcm connections to be loose, unless they where messed with during the install (maybe for reverse), but its not too much trouble to double check, i would expect if the connections where loose, anything wired into that plug would intermittently stop working (not try to operate on its own)

as another easy thing to try, i would disconnect the battery for an hour, then reconnect it, i know from experience, that some of the models of remote start bypasses will temporary change the programming in some of the cars systems that communicate through the same data bus that the gmos's work on, so in theory it could be possible for the same thing to happen with a defective gmos, and disconnecting the battery will reset the computer for the R/S modules

I did disconnect the battery for a couple of hours right after this problem started, and unfortunately it didn't help. The odd thing is the issues seem to have gone away over the weekend. The car is behaving 100% as it should... I now have a regular wire harness and am going to try installing the pioneer without the GMOS and see if that works any better...

you may need to run a new acc wire to the radio from a key powered power source, since the Gmos's get there turn on signal through the data bus, but thats not usually too big of a deal, just be careful where you get it from, and always test with a meter.

Just wanted to add an update, it's been a few days since I've installed the x920 using a normal (non-gmos) wire harness, and everything has been acting fine. I'm keeping my fingers crossed...

sounds like just another case of those Gmos adapters being total junk