Door Subs Not Working?

[TurboBRZ]

The other night I was soldering in a 4-channel amplifier RCA adapter to the radio harness in my BRZ. I had completed all 8 wires for the 4 speakers plus the remote turn on for the amplifier, and then I said "why not connect that optional ground on the adapter to make sure there is no distortion?".

So I got out my power probe and hooked it up to the battery, and then I went to my radio harness to see which of my wires was a constant ground. I tested the wire with the accessory power off, then turned the accessory power on and tested it again - it was a constant ground. So I turned off my accessory power and wired the optional ground to the radio harness (keep in mind all systems were working perfectly until this point).

I then plugged in my radio and put it in my dash, hit the ON button and nothing... No power to my dash, no power to the radio - and no accessory power. So I began checking fuses. The Radio (interior) and MPX-B fuse in the engine bay were blown. So I cut the new ground wire I had just soldered in (undoing my last step) and put a new 7.5A fuse into the MPX-B slot. The moment I put in the fuse it popped.

I got my multimeter and tested the voltage through the MPX-B fuse, which is fluctuating between 8-9V with the fuse blown. The amperage is very low (below 100mA). I then tested the other fuses in my engine bay and interior - none of them are drawing any voltage - the meter reads 0.00. I am now trying to figure out how the fuse could blow with less than 100mA present...

I'm now waiting for some new fuses to arrive as no one sells packs of the 7.5A fuses for this car! Gotta love Toyota and Subaru for that one - considering there are literally 20 of these fuses in our car. Just wanted to post this and see if anyone has any insight. I can't comprehend how wiring a ground to ground caused the fuses to pop, nor how the fuse popped again after I cut the wire I had put in... Everything done up to that one wire worked perfect. Now nothing works.

[TurboBRZ]

My fuses arrived today, but since the last fuse I put in popped immediately as I put it in, I thought with how strange everything is that perhaps there is just a relay or switch somewhere that is stuck ON. So I disconnected the negative terminal of my battery for about 30 seconds, then re-connected it. I plugged in my fuse and saw a tiny spark, but it didn't blow - phew!

So I replaced the radio fuse and it likewise stayed in tact - and then I hit the ON button and I got power to all my accessories and dash again. I haven't done anything different from the last time I put in a new fuse - other than disconnect the battery to "reset" any electronics.

[TurboBRZ]

So I wound up discovering the cause of my issue, and it had nothing to do with my ground - rather a plug that I put into the back of the head unit that doesn't go there. Quite honestly this is stupid engineering on behalf of Toyobaru for making a single plug that can go into 2 different locations within a 10" area - but what can ya do?

There is a white plug that goes to the heater/ac controls that can also plug into the back of your head unit. DON'T DO IT:



Apparently there is no connector that goes in the hole with the red arrow above... Or at least none that I could find. After I removed this connector from the head unit I stopped popping fuses left and right.

So you'd think my problems would be over right? I wish. Everything I do on this car is one step forward, two steps back...

Now my door subs aren't working... The brown amp turn on wire has 12V (tested) with the stereo turned on and speakers working, but the front subs aren't playing any bass. The front mids and tweets work just fine. All of my fuses are fine (ALL of them). Someone please help

[TurboBRZ]

So I looked at the wiring diagram again and the two door speakers alone are run by the amplifier in the back of the car. I checked the 12V turn-on wire for the amp, and it has 12V (at the amplifier).

I then moved to the speaker input wires which have no polarity (+ or -) leading me to believe that somehow they have shorted. Because there is no input polarity, all 4 of the speaker out wires are negative (grounds) and thus the front door speakers are not receiving any signal.

The strange thing is that the front door speakers and front mids and tweets share the same wires from the stereo head unit; however the wires split off to where one set goes to the rear amp for the front door speakers and the other wires go to the mids and tweets (powered by the head unit alone). So for the front mids and tweets to get a signal when the front door speakers (at the amp) have no signal makes no sense to me. I soldered all wires at the connector on the back of the head unit - not after the split (The D49 Junction Connector) where it goes to the back amplifier.

Can anyone make sense of this? I seriously cannot be the most knowledgeable person on here when it comes to wiring, and yet I've had zero responses all day...

[PNW-BRZ]

Crummy pic, but my '15 BRZ Ltd has a 10pin with a single grey wire that goes in that slot. I have a bunch of questions as well about wiring, but I'm not going to hijack this thread.

[TurboBRZ]

Originally Posted by PNW-BRZ

Crummy pic, but my '15 BRZ Ltd has a 10pin with a single grey wire that goes in that slot. I have a bunch of questions as well about wiring, but I'm not going to hijack this thread.

Mine has had that grey wire cut by the prior owner... He also cut off what I think is the auxiliary plug for an iPhone or any other device, but the door speakers worked on arrival.

[Chimera]

Originally Posted by TurboBRZ

So I looked at the wiring diagram again and the two door speakers alone are run by the amplifier in the back of the car. I checked the 12V turn-on wire for the amp, and it has 12V (at the amplifier).

I then moved to the speaker input wires which have no polarity (+ or -) leading me to believe that somehow they have shorted. Because there is no input polarity, all 4 of the speaker out wires are negative (grounds) and thus the front door speakers are not receiving any signal.

The strange thing is that the front door speakers and front mids and tweets share the same wires from the stereo head unit; however the wires split off to where one set goes to the rear amp for the front door speakers and the other wires go to the mids and tweets (powered by the head unit alone). So for the front mids and tweets to get a signal when the front door speakers (at the amp) have no signal makes no sense to me. I soldered all wires at the connector on the back of the head unit - not after the split (The D49 Junction Connector) where it goes to the back amplifier.

Can anyone make sense of this? I seriously cannot be the most knowledgeable person on here when it comes to wiring, and yet I've had zero responses all day...

The rear amp should have its own fuse, it's a 10A fuse, have you checked it?

Edit: also are you sure you checked the right wires for the rear amp, its wired.. funny
see this thread:
http://www.ft86club.com/forums/showthread.php?t=42239

[TurboBRZ]

I have checked every fuse in the engine bay and dash - there are none that are currently blown.

The rear amp is wired quite simple actually. There are 4 input wires (R + L) from the head unit and 4 output wires to the door speakers (these do NOT connect to the mids and tweets as the person referenced in the link you supplied). The problem is I have no signal on my input wires.

At the head unit (where I soldered in my 4-channel adapter) there are only 4 sets of speaker wires (FR, FL, RR, RL) which is where I wired into. The FR and FL speaker out from the head unit then go to a different connector (D49) where the signal is split with 1 set of wires running to the each set of mids then tweets, and the other set of wires going to the rear input on the door speaker amplifier. The problem is that I didn't touch the D49 connector - and my mids and tweets are working which means they have a signal.