Bose trunk harness
 

Thanks alot for your answer, firebirddude. I misunderstood how where the PAC goes. I thought it went in the trunk, but it goes to the HU.

This being said, sorry to ask this question but I’ve been searching these threads for the whole of last week and I’m going slightly mad. Can someone please tell me if the kind of harness I want can be created:

There is a (female) black and blue plug that goes in the Bose amp in the trunk. What I would like to have is an Y type cable where you have at one end a male equivalent of the female plug that plugs in the bose amp (so you can plug this male plug in the female plug which is now out of the bose) and at the other end a female plug (to plug back in the bose amp) and another male/female plug (at this point it doesn’t matter) so I can tap those wires for my LOC. So - male plug goes in the female plug that used to go in the bose amp and then it splits into the following: new female plug to go back in bose amp + another plug to tap signal for LOC.

or even just an extension for the cable that goes in the bose amp would suffice, so I can splice into something that is not part of the original system.

Can this be done? I just appreciate how tidy the whole bose set up is and as much as possible I would like to keep it intact.

Thank you.

Thanks a lot. I’ve been reading the loc discussion thread and they seem to agree there that the problem which caused Cactusgeorge’s HU to fry is not the signal strength but the fact that he connected the - of HU to the - of the amp (and we know that the - of the HU is not really ground but inverted polarity of the +) and this is what shorted it.
Taking this into consideration, if an amplifier (such as the kicker cx300.1) says it accepts differential-balanced input, am I safe then to connect the headunit output directly to its low level (not speaker level) input?

Also, PAC specifically say their passive LocPRO LP5-2 works with premium Bose systems and that it has differential inputs. Does this mean the signal strength taping before the amp will be alright then?

A T-harness at the Bose amplifier plugs does not exist as far as I know.

Kicker is one of the few exceptions to the problem you're describing/worried about. Kicker's input stage allows for isolation from the factory head unit. Yes, you can absolutely run the speaker wire from the factory head unit directly into the CXA300.1. Kudos to Kicker for that feature. That's what happens when you have a real team of US-based electrical engineers versus buying a random amp design off-the-shelf from China.

The Pac LP5 is just your standard LOC. I mean, it's a decent one, but there's nothing really special about it. If you're going to use ANY LOC, I'd tap in after the Bose amp for the same reasons I described above. You're taking a very low level signal and knocking it even lower if you tap in before the amp. If you want to tap in before the Bose amp, either run directly into the CXA300.1 or use a powered LOC like the Audiocontrol LC2i.

Bose amp T-harness
 

Thanks a lot for your reply. So this must mean that the input stage of the Kicker has something similar to a built-in powered loc/line driver in order to accommodate for balanced signals. Pretty cool. Thanks for the info.

BTW I searched a lot and actually there was a T-harness for the bose amp, but it has been discontinued. It was the PAC ADDGM-24A (apparently the input plug to the bose amp is the same for GM): https://www.sonicelectronix.com/item...ADD-GM24A.html
probably Bose sued them and they had to stop making it??

I’m really pissed that there seems to be no way to get it as I can’t find it for sale second-hand at all. Another way would be to buy another bose amp second hand and do some violence to it to get the plugs of the PCB, but that’s kind of cruel :)

anyway, this is a very helpful thread and I learned a lot here. Thanks firebirdude for your prompt replies and thanks to everyone else here. Cheers.

So it’s not really clear if there’s a lower cost alternative to the Metra Axxess kit for getting the HVAC controls to function on a competition car that has the radio removed? Which I already determined that three DPDT switches can be wired in to control the three air modes on the unit, but since the original panel switches are all there it’d just be cleaner for a PnP option if the cost is reasonable. It really seems like it’d just be a matter of getting the right wires to connect, but I’m not entirely sure about whether there’s more to it than that. Studying the electrical diagrams it seems like the radio connections are all for the audio components. So I’m a bit baffled about what is going on with the radio that ties in with the HVAC other than the CanBus and communication to the center dash display panel. So maybe there is more going on there than just simple wiring connections. I can’t really justify a (often buggy it seems) Metra kit over drilling and mounting three toggle switches if it comes to that.

I have similar problem. Dunno what kit I have, but I completely cut off my unit to stop the the hissing. My only question is if you have be using an aftermarket head unit for a couple years on a bose system , do you still need to follow your guidelines for a Bose amp. I feel like if you replace head unit and amp, it's no longer a Bose system??

Some questions regarding the Metra Kit
 

Hi all, this is my first post here.

I've recently just installed the Metra Kit on my '04 UK Spec RX-8.

The A/C itself is working fine (automatic A/C included), but my controls aren't always responding when I adjust the knobs for the temperatures and speed. The button for re-circulation is also not functioning.

From what I see, a quick workaround for the re-circulation by Metra is to have the A/C on a different setting (blowing towards the foot) but I'm not sure whether this is supposed to be the case.

Is anyone else experiencing the same? Is this to be expected?

The current firmware version I have is 2.0.