Common Ground?

[Compjake 10+ year member]

Is it possible for a common ground car to kill 3 head units?

I ran new pos and ground to my rear 5x7's but both my front speakers share the same ground wire. Could that cause a HU to fail?

I ask because my 3rd HU failed today after about 1 hour of use and it was installed exactly as the manual states.

If you got any advice on how this is happening please speak up.

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[DBBOOM 10+ year member]

Have you checked the voltage at the HU with a DMM?

 

[Compjake 10+ year member]

Yes, it reads 14.80 volts unless I got it turned up loud. then I read 14.58 at the lowest.

 

[DBBOOM 10+ year member]

Type of HU? How many channels?

 

[Compjake 10+ year member]

The first was a Jensen MP6212 it still powers on but has no sound output at all.

The second was a Power Acoustic PACD-507 and it only outputs sound from the Sub outputs.

The Third is a brand new (as of the 23th and installed the 26th) Pioneer DEH-P4000UB.

All are 4 channel.

I once used the Jensen unit at 19.80 volts fine so I know the 14 volts they get now is not the problem.

 

[DBBOOM 10+ year member]

If its four channel, it should have 4 +s and 4 -s, no reason to be sharing grounds right?

 

[snoopdan 5,000+ posts]

sharing grounds FTL...dont be cheap, go out and buy some damn wire.

 

[Compjake 10+ year member]

The stock wiring was the front speakers shared grounds and the rears had no ground. (common ground system) I didn't see the front speakers sharing grounds as a problem. but could that be why my HU's keep failing?

 

[mokedaddy 5,000+ posts]

The stock wiring was the front speakers shared grounds and the rears had no ground. (common ground system) I didn't see the front speakers sharing grounds as a problem. but could that be why my HU's keep failing?

Yes it can short out the amps. Run new wires to the fronts as newer units are not meant to be wired common ground.

 

[DBBOOM 10+ year member]

The stock wiring was the front speakers shared grounds and the rears had no ground. (common ground system) I didn't see the front speakers sharing grounds as a problem. but could that be why my HU's keep failing?

I would run dedicated wires for the speakers. Probably fix the issue.

 

[Compjake 10+ year member]

So after I do that if my HU fails again what should I look at?

 

[DBBOOM 10+ year member]

Yellow pages for a reputable local shop.

 

[mokedaddy 5,000+ posts]

So after I do that if my HU fails again what should I look at?

A new hobby. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

But really it shouldnt be that difficult to install a radio in an old car.

 

[pentavolvo 10+ year member]

are they 4 ohm speakers

 

[Compjake 10+ year member]

heh, the speakers are SSL's I wouldn't be surprised if they where 16 Ohms xD.

But yes, in all seriousness they are rated as 4 ohm.

I got my next head unit, new rear speakers and 125 feet of new speaker wire. I will let you guys know tomorrow if everything ok after I rewire all my speakers.