No signal to rear speakers

[M@c 10+ year member]

I thought I,d start slow but already stumped. I installed a 600w amp. and new front and rear speakers in 2002 GMC Sierra Denali. I cut the front speaker wires 6" behind the radio plug and installed a adjustable line output

converter for RCA jacks. I couldn't locate the rear speaker wires in the harness - I installed the converter behind the rear seat near the new Amp. And ran new speaker wires to the rear speakers. For the front I only ran speaker wires to where I cut the stock wires behind the head unit. I located a unused pin that switched to + when the head is turned on and used this for the amp. remote trigger.

Problem is only channel A (front speakers) is working when the amp

is on 4 channel. On 2 channel front and rear speakers work, so I know

rear speaker wires and speakers work.

I switched the RCA jacks so the rear speakers channel was in channel A and still nothing.

So I took the old speaker and reconnected it before the converter to check rear (channel B) output from thre head and nothing. I also put the front RCA (channel A) in the channel B RCA input and the rear speakers worked so I know the amp. channel is working. I also know the rear speakers and fader was working before.

Any guesses how I lost the rear channel output from the head?

Any one have a guess as to what happened to my rear channel?

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[M@c 10+ year member]

Any suggestions

 

[boogeyman 10+ year member]

Do you have a 4 channel LOC? Or 2 2 channel LOC,s. That is what you need. 1 for the front 1 for the rear, or 1 4 channel LOC.

 

[M@c 10+ year member]

I have 2 - two channel LOCs. For the front speakers

I cut the wires a d installed in behind the head. The weird thing is

the rear speaker wires don't show up in the harness behind the head, so I installed the tear LOC behind the rear seat - pulling on speaker wire out of the door and running it near the other speakers wire near the amp. Which I cut to install the LOC. and then ran new speaker wires from the amp. to the rear speakers. The weird thing is there is no signal now in those rear (stock) speaker wires running from where ever (they don't show up in the harness behind the HU) to the LOC. I attached a speaker in front of

the LOC to test and nothing. The only thing I did that affected the stock setup was cut the front speaker wires behind the HU. Connected the LOC and ran wires from the amp to the stock front speaker wires at the same cut, this is channel A and works.

How come the rear speaker wires don't show up in the harness behind the HU? Dark blue light blue = rear right and brown yellow = rear left and they aren't in the harness.

 

[M@c 10+ year member]

So I thought I had screwed something else since when I opened my

door the HU didn't turn off. It was because I still

had the door panel off and the electric lock

switch must control it.

After terring into every crevas tracing the rear speaker wires I found them at the rear passenger control unit that I took off so I could pull wires. Now everything is working fine.

Lesson learned - plug everything in while testing.

 

[M@c 10+ year member]

Thanks!

 

[M@c 10+ year member]

Thanks!