Adding an Amp with GMOS-04 Harness

[Daddy Riffs]

Hello All,

Great site, first of all, learning quite a bit. My dilemma:
A while ago the stock radio died on my Envoy. I replaced it with a cheap Pioneer unit, DEHP7400HD, till I can get the funds for a DVD/Navi unit. I used the GMOS-04 harness because of the old lady wanting to hold on to Onstar, even though we have 4 cell phones, and the Bose UQA code, RAP, and Bells. Everything works great but the HU is not loud enough, in my opinion. I read all the posts in this section and if I missed the answer to this I apologize, but how do I wire an Amp to the system. Do I just run the RCA's from the HU to the amp and then run the speaker wires from the amp to the speaker cables on the GMOS, and run the output of the amp through the GMOS speaker "in" wires that will then send the signal to the Bose speaker amp and then to the stock speakers?

I've installed a few amps in the past but never one with existing built-in Bose amps. And I usually did just that, ran RCA's from HU to amp, and then splice the speaker cables from amp to the stock speaker wires behind the dash. BTW, the speakers and the amp are good the stock unit still plays AM stations and it sounded normal and loud, as the stock units do, prior to and after the new HU install. So I would appreciate clarification if this is the way it's done, or if I need more harnesses and adapters and what-not.

Thanks in Advanced.!!!

Daddy Riffs

 

[NinjuhhNutz]

Hello All,

Great site, first of all, learning quite a bit. My dilemma:
A while ago the stock radio died on my Envoy. I replaced it with a cheap Pioneer unit, DEHP7400HD, till I can get the funds for a DVD/Navi unit. I used the GMOS-04 harness because of the old lady wanting to hold on to Onstar, even though we have 4 cell phones, and the Bose UQA code, RAP, and Bells. Everything works great but the HU is not loud enough, in my opinion. I read all the posts in this section and if I missed the answer to this I apologize, but how do I wire an Amp to the system. Do I just run the RCA's from the HU to the amp and then run the speaker wires from the amp to the speaker cables on the GMOS, and run the output of the amp through the GMOS speaker "in" wires that will then send the signal to the Bose speaker amp and then to the stock speakers?

I've installed a few amps in the past but never one with existing built-in Bose amps. And I usually did just that, ran RCA's from HU to amp, and then splice the speaker cables from amp to the stock speaker wires behind the dash. BTW, the speakers and the amp are good the stock unit still plays AM stations and it sounded normal and loud, as the stock units do, prior to and after the new HU install. So I would appreciate clarification if this is the way it's done, or if I need more harnesses and adapters and what-not.

Thanks in Advanced.!!!

Daddy Riffs

You're trying to amplify the head unit speaker outputs, and THEN go to the factory Bose amp? That's a no-no
The bose system is designed to work together, and play nicely together with our trucks. That's why the harnesses are a must when replacing the HU, when you take the bose HU out of the picture, a component of the Bose system is being replaced with something that isn't originally designed to fit into that circle of fun lol

Long story short, keeping the entire Bose system together, will (at least in my experience) yield a higher quality sound than it would if you simply replace the head unit alone. There are guys that have swapped every bit of the sound system, (HU, speakers, amp, subs, all the way down to the wiring) and it sounds 10X better than the factory bose
With that said, higher quality doesn't mean higher volume...so, I guess it really comes down to what you want in the truck.
Just out of curiosity, how loud does it get? You said it isn't loud enough? I haven't come across an issue where any aftermarket HU was considerably lower in volume than factory

 

[STLtrailbSS]

The best way to get better sound.....get rid of Bose and redesign yourself.

 

[Black LT]

You're trying to amplify the head unit speaker outputs, and THEN go to the factory Bose amp? That's a no-no
The bose system is designed to work together, and play nicely together with our trucks.

That.

If you want to add an amp for the door speakers you could run the rca's to the new amp then cut the door speaker wires on the 'out' side of the factory amp - cap off the wires you just cut coming out of the factory amp and use the new amp to feed the other side of the wires you just cut that go to the speakers.

But as stated, when part is replaced other parts will seem to need replaced.

Some people get a happy set up - others aren't happy till it's all redone.

 

[Daddy Riffs]

Thank You for all the quick responses. Good thing you guys are here I could have done a baaaaaaad thing.!

So basically what you are all saying that there is a way to by-pass the amp, or get rid of Bose all together. I will admit that the whole GMS04 harness was a new experience and an easy one to do. I really do not want to get rid of the Bose system I want to keep as much original stuff in the truck as possible, and although the thought of by-passing it might sound good it would still be canibilizing it a bit, I even thought to get the original radio fixed or replaced, but I am falling in love with the DVD/Navi units out there, gotta keep saving. Which is why I asked you gents in case I get the same result when I install the Navi unit.

The Pioneer does get drowned out if I open the windows, I don't like to use the AC if possible, so it's really soft in volume. All I wanted was to get more volume so that I can hear the music when the windows are open. I thought that the 12 watts, actual output of the pioneer, would at least come through and provide a bit more volume and at least be as loud as the original HU.
If any of you have any other suggestions please feel free. As I said I am learning a lot from here and I look forward to learning even more..

Regards,
DR

 

[jonbo2002]

anything going through the bose amp is only going to be powered by the amp, if you get a higher wattage HU it won't add to the power of the amp. If it was loud enough with the bose HU in I would just replace it and get a tomtom or garmin lol. otherwise you need to bypass the bose amp and wire directly to the speakers. I dont have bose in mine but my old Grand Marquis had a factory amp and when I put in a new HU I wasn't happy with the sound till I direct wired the speakers to the new HU.

 

[NinjuhhNutz]

Thank You for all the quick responses. Good thing you guys are here I could have done a baaaaaaad thing.!

So basically what you are all saying that there is a way to by-pass the amp, or get rid of Bose all together. I will admit that the whole GMS04 harness was a new experience and an easy one to do. I really do not want to get rid of the Bose system I want to keep as much original stuff in the truck as possible, and although the thought of by-passing it might sound good it would still be canibilizing it a bit, I even thought to get the original radio fixed or replaced, but I am falling in love with the DVD/Navi units out there, gotta keep saving. Which is why I asked you gents in case I get the same result when I install the Navi unit.

The Pioneer does get drowned out if I open the windows, I don't like to use the AC if possible, so it's really soft in volume. All I wanted was to get more volume so that I can hear the music when the windows are open. I thought that the 12 watts, actual output of the pioneer, would at least come through and provide a bit more volume and at least be as loud as the original HU.
If any of you have any other suggestions please feel free. As I said I am learning a lot from here and I look forward to learning even more..

Regards,
DR

I may be wrong, but if your windows are drowning out your sound system, then there is something going on somewhere else
have you double checked and made sure all your speakers are working properly? even with balance/fade set to one corner, I can still hear my music with all 4 windows down and sunroof open (which is pretty much how I always ride anyways :wootwoot:

 

[Dad-O-Matic]

I may be wrong, but if your windows are drowning out your sound system, then there is something going on somewhere else
have you double checked and made sure all your speakers are working properly? even with balance/fade set to one corner, I can still hear my music with all 4 windows down and sunroof open (which is pretty much how I always ride anyways :wootwoot:

. I'd double check all your connections. I have the stock Bose with a JVC HU and a GMOS-014. I believe it's essentially the same as the GMOS-04 but with RCA jacks for the rear DVD. The best sounding stereo I've ever had, the bass will rattle the mirrors and shake the floorboards.

 

[Black LT]

Yeah, check your GMOS-04 directions. I think there's a gain control on it.




But if you do what I said in my previous post, Your door speakers would be powered by the aftermarket amp and the dash speakers would still be powered by the factory amp - retaining the chimes and onstar that she wants (they play through the front left dash speaker).

 

[Daddy Riffs]

Wow, you guys sure know your Car Audio stuff. I checked and double checked all the connections and they were correct. I even called Crutchfield to make sure they were right, and even had them explain why there were 2 red wires. Asked if there was an adjustment other than the chime volume for audio output and was told there wasn't one. So here is what happened after that:

I remembered that the Chimes were a bit too loud out of the GMOS and turned it down a bit when I first put in, so I turned them back up a bit and guess what? The volume output of the HU also increased, so I thought could this be a defective GMOS? A friend that has a 05 Monte Carlo, had just pulled the original HU but used a 38.00 Scosche 2000 harness that he bought at Wally-World and told me to try it, although it did not do Onstar it did do RAP and chimes. So I went to Wally-World picked up a Scosche 2000 and WOW...!!! Now I can't hear myself think at 2 or 4 on the volume dial. I think it's time to convince the old lady to get rid of Onstar and just use her cell in case of emergencies and keep this thing just like it they are now.

Has anyone else ever had that issue with a GMOS? You would think that harness valued at 100 bucks would be more reliable and worth it. Here a 38.00 harness is running circles around Metra, I guess you don't always get what you pay for...!

Thanks to all of you who replied and guided me in the right direction and prevented me from doing a no-no... I will be coming back if I ever have another issue. THANKS A LOT GUYS/GALS if there were any of them here...!

Regards,
JGM
Daddy Riffs

 

[NinjuhhNutz]

I bought a used gmos on ebay and it didn't function properly, so I'm SOL with my head unit.until I can get a new harness

Glad to hear everything worked out for you! I'll add the "check your gmos control" to my check list now
Hell, I learned something from this thread myself

 

[Daddy Riffs]

Reading that you too learned something on this thread makes me feel useful and part of the group... LOL

 

[NinjuhhNutz]

Hey man, that's what's it's all about!