So I recently did the dash mod and installed a double din. I have the premium factory unit with amp and the former stock radio was the Alpine. The problem I have is that the volume seems like it should get much louder. I used the Metra 1786 adapter and had to order a diversified antenna harness for the two antenna leads from the car as I was only pulling in one station with just the large antenna plugged into the new unit.

As for the volume. When turned up almost all of the way, It seems only half of what the original did and I will get an occasional pop/scratch sound.

I scoured the old post and nothing seemed to describe my issue. I am pretty sure that I have this wired correctly as I am assuming since the 1786 uses the pre-outs on the new radio I would either have sound or not as they are running through the amp. The amp also get warm to the touch.

 

Does your head unit have a "sub-woofer" setting? When I did my swap it was "ON" by default when it should be "OFF" and the sound was not good. When the setting was "ON" the head unit shut off one of the outputs and substituted what it thought was a signal going directly to a sub-woofer. This is not the case for the high-line audio system as the amp expects just a full frequency audio signal and it takes care of speaker and sub-woofer mixing and crossover.

 

It does have a sub settings. I will have to check that out.

 

The onboard amp won't power up unless it receives a trigger signal. What is your new head unit?

 

Kenwood 2-DIN 6.8” Touchscreen Car Stereo Digital Multimedia Receiver *DMX125

Its possible that I did not get the blue amp wire connected correctly, I followed the instructions of the metra and Kenwood.

Wouldn't I have no sound at all if the amp was not on? I could also see that I misswired and from what I read on here is that the amp also triggers the antenna amp as well. Sad thing is, I used to be an audio installer. But that was back in the 90's though.

 

Well I got the diversified antenna adapter and the mini GM to Motorola adapter and all radio channel come in now! Seems a bit louder (but not really).

I still got that horible scratchy/thump sound though at higher volumes (I'm a metal head).

the amp is definitely powered as I rechecked my wiring. And the antenna is also boosted as from what I understand is ran by the amp trigger as well.

talking with another former installer, he was curious about the 70-1786 harness using pre outs. When checking Crutchfield it only list that harness for the Harmon system but everyone here has been using the 1786 I looked at the harness and see they split off to two separate speaker wires. He also wondered about what the impedience of the speakers are. Without removing them I have no idea and can't find anything out in the rave regarding such.

if anyone has any ideas on this, chime in!

 

I have read all of this before but can not remember exactly and am in no position to do the research again...

From what I recall the small antenna wire is for the NAV system, If you have the diversified AM/FM system (some didn't) then they are wired together in the harness under the heeadliner above the cargo area. The antenna RF amps are located below the Alpine windows so you don't really have to remove the headliner to inspect.

I remember the speakers being low ohm, 2 or 4... The amp under the drivers seat takes line level so that would be the PRE AMP OUTS of your new head unit. RCA Cables.

I have a Kenwood head unit and have the front door speakers and sub powered by a separate 3 channel amp. The preamp outs feed the under seat amp which feeds the rear door speakers which in the case of my vehicle are a low a frequency driver.

That's all I got but it is all out there on the internets.

 

What exactly is the "diversified antenna adapter and the mini GM to Motorola adapter" and where can I order it?

Installing a Kenwood head unit and trying to sort out the diversified antenna. I use the radio a lot so I would like the reception to be as good as the stock unit.

Tried to get the one from "Mobile Emotions" mentioned in other posts, they appear to be a zombie site now. Took my order but a month later hasn't shipped and they do not reply to phone or email.

Thanks!

 

I’ve been looking for this information everywhere. So a standard single to 8 channels on the input is enough? I wasn’t sure if the amp had a built in crossover.

 

Here are the adapters I got for mine. My radio would not work with just the fm plugged in. But for whatever reason I do not have an a.m. signal in mine. Could be the radio I got as it was a refurb but i dont use a.m. anyway.

You will also need another adapter since one of the male inputs is a mini size.