This isn't my first time installing a stereo, but it is my first time installing a all in one stereo/nav/bluetooth head unit so I've run into a slight deliemma that I'm unsure how to deal with.

I'm installing an AVIC F90bt. My metra wiring harness from the car has a ground connection, normally I would connect this wire up to the ground wire from the AVIC F80bt harness.

However the wire itself isn't really set up to be connected to the wiring harness ground but instead it appears set up to be connected directly to the chasis. And the directions aren't very clear about hooking this wire up.

So should I connect the ground wire from the AVIC harness to the Ground wire from the Metra harness? Or should I directly ground the unit to the chasis? I would assume they are the same...but I wasn't totally sure and didn't want to wreck the unit even before I got it installed.

Thanks for any help.

This isn't my first time installing a stereo, but it is my first time installing a all in one stereo/nav/bluetooth head unit so I've run into a slight deliemma that I'm unsure how to deal with.

 

I'm installing an AVIC F90bt. My metra wiring harness from the car has a ground connection, normally I would connect this wire up to the ground wire from the AVIC F80bt harness.

 

However the wire itself isn't really set up to be connected to the wiring harness ground but instead it appears set up to be connected directly to the chasis. And the directions aren't very clear about hooking this wire up.

 

So should I connect the ground wire from the AVIC harness to the Ground wire from the Metra harness? Or should I directly ground the unit to the chasis? I would assume they are the same...but I wasn't totally sure and didn't want to wreck the unit even before I got it installed.

 

Thanks for any help.

It's no different from any other car stereo install, if you've got a solid black wire for ground in the Metra harness, use that for the AVIC (if you choose to hardware bypass, then add the parking brake line, and the line you moved in the harness)

Having a spade lug on the ground has been standard in the US for over 20 years, it's just to help in case your OEM harness doesn't have a true black ground wire, doesn't means you *must* use the spade.

I installed my F series this weekend and having an issue with the ground. First I tied all the grounds together and attached to the car. I was getting a terrible buzz when the car was running and also had alternator whine. After a lot of reading, I tried grounding the rca outputs. This didn't help. I am installing this with a Metra 70-7551 harness for a Nissan with the Bose amp. I decided to change the ground from the car to the harness. Doesn't make sense, but worth a try. I left the bypass wires grounded to the car. This still has terrible humm when the car is running. The system sounds fine if the engine is off. I tried grounding the RCAs and no change. I remove the RCA grounds and checked continuity from the rca shields to the car and it was good. I assume this means the pico fuse is still good???

Not sure what I was trying, but I eventually noticed that if the headunit did not come in contact with the car ground, the buzz was gone. So I put some carboard spacers between the mounting brackets and the car. I left the grounds in the harness, except for the bypass, and now I only get a faint buzz that is only noticeable at start-up or 0 volume. With the set up, I can not use the screws to secure my headunit to the car, so it is just secured by the dash cover. Its a tight fit, so its not bad, but does bother me.

I am lost on why the buzz and humm starts up if the headunit case is in contact with a ground. Same thing if I isolate the headunit and try to ground the RCA connections. I get a loud buzz immediately in either case.

I don't see where anything could be connected wrong. With the metra harness the connections were red, yellow, orange, blue, blue/white, and black (2x), plus the F/R RCAs. Everything matches up like it should. I moved the y/b mute and grounded the light green brake. The bypass works. The purple reverse is not connected, the RCAs for the sub are not connected. Sub is off and rear speakers are set to full.

Any suggestions? Also I soldered the harness connections before installing it and I removed the ground from the battery before I started the install. I completed all connections before putting the ground back on the battery.