Hey, I am just about at the end of my rope here. Can someone please tell me why my Sony head unit works fine in my '92 240SX, but when I put my Aiwa unit in (same wires, same plugs) there's no rear sound and mute is permenantly engaged? I had it taken to a service shop and after charging me and taking a week to look at it they said there was nothing wrong with it, and that it worked fine.

WHAT'S THE PROBLEM?

Please read this thread for more information, particularly the bottom post:

http://xscaraudio.proboards7.c...72846

There is only ONE difference in the actual wire harness plugs (that fit into the unit itself) that I can tell...the one that came with the Aiwa doesn't have a blue w/ white stripe one. That's the one that Nissan lists as being 'Factory Amp Turn On'. That's also the one that was tapped when I had my subwoofers and amp installed. So, I just left it, rather than uncrimp, strip, and recrimp all the wires, re-attach the tap, etc. Besides, the one that came with the Aiwa is unused. So the guy that had the Aiwa head unit before me (I bought it used) didn't use it either. And the service shop that checked my head unit didn't use it. So. I don't think that's the problem.

There is one main difference in the head units I should mention...The sony is slightly less powerful, it only has a 10A fuse (the Aiwa has a 15A).

PLEASE HELP! =/ Thanks so much!

-Darwin

I'm posting this without reading the forum you provided a link to. But are you aware that a lot of 240's have factory amps.. From what I made out of your post, it sounds like you left the remote power line disconnected. If so, your rear speakers don't work because the factory amp is not switching on, as a result of having no signal to tell it to do so. The s14 with the clarion system has two factory amps (front and back), and the s13 has one for each rear speaker (I think)... but that's beside the point.. you either need to hook the Blue/White factory wire to a remote on your deck, or wire an inline switch from a fused power source... cig lighter maybe.

Alright.. I just re-read your post... Did the stereo shop splice the blue/white line AFTER the wiring harness?..... YOU HAVE TO CONNECT THE blue/white WIRE FROM THE HEAD TO THE blue/white WIRE FROM THE CAR... otherwise there is NO signal to turn the amp on... The subs and amp were hooked up with your old head unit right.... and I'm going to assume the Sony head had a remote line in the wiring harness so it all worked.

Try splicing the amp, car, and head unit blue/white wires ALL TOGETHER.. I think that's your problem... give it a shot and all should be well again!!

I finally went and read your link. :rolleyes Let me just say this, for a car audio board, they seem to be kinda clueless.. (no offense to them) I'm no car audio expert.. I've toyed with them alot, but never professionally..

Anyway let me know what's up.. I've got a couple other ideas if that doesn't work out for you... but I think it will!

Wow, okay thank you VERY much! That's what I'd been suspecting, since that was the one wire that didn't match. But if the Aiwa head isn't reading the signal from the harness plug, where do I hook it to? There's one wire that's just blue, and it says 'RELAY CONTROL' 'TO POWER ANTENNA/TO REMOTE CONTROL' 'FUSE 0.5A' on the Aiwa box. The equivelant blue wire from the Sony goes to what Nissan calls the 'Power Antenna Turn On' wire. Is that the one I should tap into?

I'm kind of dense about this stuff, but I'm trying to learn. ;D I've only installed one head unit before, and that had detailed installations (Crutchfield rocks).

And what do you mean about AFTER the wiring harness? Here's what they appear to have done (I didn't watch the guy do it)...

He appears to have cut the 'Factory Amp Turn On' line (green on the car side of the harness, blue/white on the head unit side) right before AND right after the wiring harness (why bypass the harness? I don't know). Then it taps out to the sub amp, and continues straight into the head unit plug harness.

So, after typing all this I think I am understanding that the Aiwa deals with all amp/antenna/etc. relays in one line (blue); while the Sony has a seperate line (blue/white) for the amp relay(s), and the blue one only handles the antenna. If I'm incorrect let me know.

If this is indeed the case, which do I tap into which?

Thanks again for doing all this, I feel so stupid for thinking it was broken. =/ But how was I to know? And what the HELL does this have to do with mute...I hope it fixes that too though.

I'm not sure why that would affect the mute function.. that shouldn't be an issue after it's hooked up correctly.. keep your fingers crossed!

Just to clear up one source of confusion.. the Aiwa head does NOT read any signal from the harness.. it's all one way... out of the head. The amp wire, and the geen car wire receive a signal to turn the amps on. That green wire turns the factory amps on, and the blue/white wire turns the after-market amps on.

It sounds like the previous installer just bypassed the wiring harness for the "remote line". This is pretty typical for many reasons, and not at all important so I won't waste our time explaining. Splice the wire you described from the head.. "blue power antenna/remote" to the green wire in the car and blue/white amp wire.. this SHOULD solve your problem.

This is the way it works. Most any aftermarket head unit will have this "blue wire". It goes by many names, usually, "power antenna" or, "remote power" or anyother variation. When you turn on the head, it sends a small signal to your amp that turns it on. (this is to prevent damage to the amp from a power surge when you turn the vehicle on) The amp will turn off when you turn the head unit off, this is entirely meant to prolong the life of the amps. Your car has nothing to do with turning the amps on, so since your car-amps and sub-amp wires are not connected to the head, they are not recieving the small signal to turn on. hence, there is not going to be power to the amps, because they are not on... plain and simple.

I hope this has been helpful, and I hope it works... it should, if not get back to me!

IT WORKED! =D

Thank you! You made my day! =)

Glad I could help! Glad I was right.. I love when that happens!

Where are the factory amps located in an s13. And what models did they come one? thanksBrett

Actually, the S13 does not have amps, it has Active Speakers, which is a built in crossover in the front door speakers. The amp turn on wire controls these. I only wish i knew the crossover frequency.

JNM240 wrote:Actually, the S13 does not have amps, it has Active Speakers, which is a built in crossover in the front door speakers. The amp turn on wire controls these. I only wish i knew the crossover frequency.

Again.. I'm not sure how the s13 stereo works... but if it doesn't have a rear amp, and only has the front active speaker system, how does this account for his REAR speakers not operating when the remote isn't connected.

From what I have read the s13 has seperate small amps for each of the REAR speakers... besides, a crossover unit DOES NOT amplify the signal (yes there are some amps that have crossovers, but a crossover does not amplify the signal). So, if the crossover was not turned on, it would not cause the speakers to not work. I have read about the active speaker systems, from my understanding I believe it is amplifiers, not just crossovers. I'll try to find out for sure.