Is it possible to use the same front & rear speakers negative cable like this drawing? My car's factory harness doesn't have rear speakers negative connection so I'm forced to use the front speaker's negative terminal.

 

thats how alot of older oem systems are wired. ive put decks into several of the systems and never had a problem. i just used either the front or the rear neg. but not both.

 

yes you can do that.

 

Just make sure that i'm cleared.

My car have:
Front speakers positive & negative connections
Rear speakers positive only

My OEM wiring harness doesn't have REAR negative connections. I'm going to have to share the rear speakers negative wires with the front speakers right?

My car is an 88 Nissan 300ZX.

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Sorry for the dumb question

I looked it up on this guy's website (he have an 88 300zx) and this is what it saids:


Color Codes:
B = black
G = green
L = blue
LG = light green
R = red
W = white
Y = yellow

For below:
Abbrieviation = Color of wire = Long name
The color after the slash (/) is the stripe color. i.e. R/G = red wire with green stripe.
SF, GL, and SS models should all be the same.

All models:
ILL = R/G = Illumination
IGN = Y/G = Ignition (12V when key is in ACC or ON position)
12V = L/R = Always 12V
ANT = G/B = Signal to antenna
RF+ = R/W = Right Front Speaker Positive
RF- = R = Right Front Speaker Negative
LF+ = L/W = Left Front Speaker Positive
LF- = L = Left Front Speaker Negative
GND = _ = Ground = any metal contact point on the frame. SF, GL, SS (no external amp)
RR+ = R/B = Right Rear Speaker Positive
RR- = R = Right Rear Speaker Negative
LR+ = L/B = Left Rear Speaker Positive
LR- = L = Left Rear Speaker Negative


So according to him, the car use the same negative wire for front & rear speakers.

 

In this picture, all of the wires are accounted for except for the rear speakers negative connection.
I've spent several hours looking for the damn rear negative speaker connections on the OEM harness.

 

I was told that using common ground will **** your stuff up.

 

this is honda tech man not nissan tech.
how will using a common ground mess anything up??
sharing ground wires between speakers wont hurt them.

 

again.. "Heard" "told"... who ever's telling you that bs is wrong and does not know what they're talking about.. . ground is ground folks.

 

With most newer HUs you can NOT use common grounds, most newer HUs have "true" 4ch amps built in and all four channels must have the pos.(+) and neg.(-) for that channel connected to the speaker and nothing else.

With that said your car should have both pos.(+) and neg(-) leads for all 4 speakers, the stock radio has two plugs, with powers, ground and some speaker leads on one plug and the other speaker leads on the other plug... http://www.installdr.com/Harnesses/Nissan-Wiring.pdf

kroze...
"I was told that using common ground will **** your stuff up."

The advice was good, the rest your getting here is not good.

If you guys think common grounding the outputs of an after market HU or the speakers is OK, go ahead and do it with your HU, then turn it on and hope the protection circuit in the HU prevents the outputs from going west.

One more thing, there is no speaker ground, there is a pos.(+) and neg.(-) speaker output, it doesn't even make a diff. which terminal on the speaker you plug them into, as long as both left and right channels are done the same way, an amps speaker output is AC current not DC current, [DC is not what you want out of the amps outputs, very bad] 94

 

WOW! bump what FCM said!

 

Listen to this man. He all ready summed up what I was going to post. Its bettery to run new speaker sire to each speaker.