Disconnected ground wire from HU- still works... WTF???

[igo4bmx 10+ year member]

so i'm dealing with a ground loop issue and I cut the ground wire to relocate it to a better ground, but after turning the car on with this wire cut, the headunit STILL works!! also, my in dash vga lcd for my carputer still turns on too...

pioneer 880prs if that helps..

WTF

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[Silver 10+ year member]

u sure u cut the right wire

 

[azbass 5,000+ posts]

is your antenna still hooked in to it?

its probably grounded through that

 

[igo4bmx 10+ year member]

is your antenna still hooked in to it?
its probably grounded through that

i cut the black wire from the pioneer harness.

red- 12+

yellow - battery 12+

black-ground

blue-remote turn on for amps

orange -illumination...

i just removed the antenna and that did not "fix" it..

WTF

 

[blackbonnie 5,000+ posts]

some times it will get enough ground through the bolt on your mounting kit if it is touching. i dont know if it is, but ive seen that happen before.

 

[Randy Savage 5,000+ posts]

What kind of car?

 

[igo4bmx 10+ year member]

What kind of car?

its a 2000 honda civic.

i do bolt the din units to metal, which is then bolted to the chassis.

is there anything i can measure with one of those electric probes?

 

[igo4bmx 10+ year member]

this is making it real hard to diagnose a grounding issue when i can't reground it lol

 

[gl0ck 10+ year member]

antenna ground prob, i would reccomend taking the 12v away from it for fear of messing it up.

 

[Randy Savage 5,000+ posts]

2000 Civic uses a cage mount, and the only thing the cage touches is the plastic. So it shouldn't be the mounting making contact with metal anywhere.

If you have a multimeter, set it to DC. Unplug the harness, grab your constant 12v (yellow), and hook it up to one probe. Now, take the other probe, and touch every other wire on the harness till you get 12v on the meter. Whatever other wire gives you 12v is grounding out.

 

[igo4bmx 10+ year member]

2000 Civic uses a cage mount, and the only thing the cage touches is the plastic. So it shouldn't be the mounting making contact with metal anywhere.
If you have a multimeter, set it to DC. Unplug the harness, grab your constant 12v (yellow), and hook it up to one probe. Now, take the other probe, and touch every other wire on the harness till you get 12v on the meter. Whatever other wire gives you 12v is grounding out.

thanks... good idea!!

to the poster above, i already removed the antenna plug

 

[igo4bmx 10+ year member]

yellow and black - 0 v

yellow and blue - 12 v

yellow and orange - 0 v

oh yeah and it still powers on....

 

[Randy Savage 5,000+ posts]

yellow and black - 0 vyellow and blue - 12 v

yellow and orange - 0 v

oh yeah and it still powers on....

Blue=power antenna

 

[igo4bmx 10+ year member]

Blue=power antenna

so it should complete the circuit?

i'm using it to remote turn on the amps

 

[Randy Savage 5,000+ posts]

so it should complete the circuit?i'm using it to remote turn on the amps

Civic's don't have power antenna's, correct?

Been a while since I worked on one.

If you have no power antenna, the blue wire usually will lead to nothing on the factory harness side, and, if you're using the power antenna wire for a remote turn-on (which is ok), and you're getting a ground through the remote turn on, something is grounding out, somewhere.