GMOS install and a radio the refuses to turn on

[t.moteo]

Hey guys, me again, and I've run into even more issues trying to get this Alpine radio installed and was wondering if I could get some insight from someone who's maybe done this before. I wired up the GMOS and tested functionality after installing the radio and all four speakers. After that I moved to install the amp for my subwoofer. Disconnected negative terminal from the battery, put the amp power on the hot-side post of the fusebox adjacent to the battery (since the connector won't fit on the battery and I did not have a post adaptor on hand), and ran the ground strap to the bolt that the battery is using for ground. Connected everything back up and now I have nothing. The GMOS chimed when the negative terminal was connected back and continues to chime when your reconnect it to the OEM harness and doesn't show any signs of failure: no popped caps or blown chips. I've swapped the stock radio back in and out a few times while testing and diagnosing and it comes on and plays just fine but the Alpine radio will not turn on when plugged in. I've checked the audio fuse in the fusebox (f21, 10 amp), the fuse on the Alpine inline amplifer, as well as the fuse on the radio itself and all fuses are fine.

Is there a relay that may have been damaged that I'm not aware of? Is there any other point of failure on the circuit that would keep this from happening? I'm really scratching my head here as, during the amp install, I didn't hear any pops to indicate a surge, there is no physical evidence of a surge on any piece of equipment that I know to check, and everything is seemingly functional besides the radio.

Now, before anyone asks, I went ahead and tested to see if the radio simply failed as that was my first thought. I went out and bought a second radio (1st was bought on amazon and I didn't want to wait 2 weeks just to see if the radio had, in fact, failed) and it is not working either, even after rewiring the harness to GMOS.

While it has been about 5 years, I've never come across an install this difficult in my 2 years of installing car audio and I could really use some help if anyone has some.

 

[buj818]

I run nothing but Alpine decks with RF amplifiers. In the 30+ "systems" I've installed, the only wires I ever use are the power, ground, remote, and speakers. Even with these high dollar harnesses, odds are you'll never need most of the functions that the vehicle harness provides (dimmer, illumination, ect.) Because they are controlled within the unit itself. One question to ask, what ground wire do you have connected to your battery? All grounds should be as short as possible. That's how major interference occurs, with grounds being ran all over the car across circuits.

 

[t.moteo]

I do the same and bypass illumination, interrupt and antenna (especially since the Buick doesn't have a power antenna). The ground wire I ran was for the sub amp, located in the trunk.It has since been removed during my troubleshooting period and I'll most likely relocate it to the center seat belt bolt as going to the battery ground was a bit of a stretch. The ground for the radio is going to the GMOS.

 

[buj818]

Ill be honest, I don't have a clue what a GMOS is. Always used the cheap old Scoshe adapter harness with optimum results every time. If you take radio out, and touch ground to batt negative, and red and yellow wires touching batt pos, hit the source button (or in some cases with Alpine the tiny reset button), the deck should power right up.

- - - Updated - - -

That should be a good test to determine the deck is good. Just try to get some straight up basic power to it. Then when confirmed, we will rock it from there.

 

[t.moteo]

GMOS is the system used to maintain the data link connections from the '00+ GM vehicles so they can maintain Remote Accessory Power, ONStar, and Steering Wheel Controls. I don't have either of the latter but it keeps it simple and prevents you from having to make a jumper from the ignition harness in order to get the radio to turn on in the first place.

I will go ahead and try the direct connection to the battery either when I get home tonight or in the morning before work.

 

[t.moteo]

Picked up a multimeter last night and tested 12v constant = good, ignition = fail. Ran out and bought a new GMOS interface this morning and we're back up and running!