Chassis ground with head unit install?

[Chris]

I got a new Kenwood headunit for my TJ. I ordered it from Crutchfield and it came with the Metra harness so that you can plug it into your factory harness without having to cut it.

When looking at the Metra harness, it has a black wire, and then the harness that goes into the Kenwood headunit also has a black wire, which is extra long which according to the wiring diagram is the, "Chassis Ground". I'm unsure on whether I splice the two black wires together, or if I am suppose to ground the long black wire to the chassis behind the dash, and not splice it to the other half of the harness at all?

Here's a photo:

 

[cliffish]

I spliced them, the head unit is going to get a good ground from the metal sleave that holds it to the dash.

 

[Chris]

I spliced them, the head unit is going to get a good ground from the metal sleave that holds it to the dash.

Okay, that's what I figured as well, just wanted to confirm!

 

[Chris]

I spliced them, the head unit is going to get a good ground from the metal sleave that holds it to the dash.

Oh, how about the "illumination" wire? Does that get spliced to anything? I ask because there is no color matched wire for it.

 

[cliffish]

not sure what the illumination wire is, what color? if blue that is usually used for the amp remote turn on.

 

[Chris]

On the Metra wiring diagram, it says the illumination wire is the orange one.

 

[cliffish]

can you line it up with the factory harness and look that wire up for what it does? I am assuming it is what dims the radio when you turn on the headlights, can't remember what I hooked it up to on my Sony.

 

[cliffish]

just looked at the manual for my Sony and my head unit had a orange/white wire marked for illumination. Look in your manual for the head unit wiring, has to be there

 

[cliffish]

I just found the manual for your radio and it does not show any illumination wire to the head, I wonder how it handles it when you turn on your lights at night?

 

[Chris]

I just found the manual for your radio and it does not show any illumination wire to the head, I wonder how it handles it when you turn on your lights at night?

Yeah, I'm looking at the manual and I don't see any illumination wires at all. I don't get it... Maybe I'll call Crutchfield tomorrow and see what they say. I'm used to there always being an illumination wire... At least there's always been on headunits I've had on past vehicle.

 

[Drizit]

I've run into a few where there's no illumination control. When you power on the radio the back light comes on with it. There may be brightness control in the menus.

—
There must have been a time
when we could have said no.

 

[skrelnik]

I got a new Kenwood headunit for my TJ. I ordered it from Crutchfield and it came with the Metra harness so that you can plug it into your factory harness without having to cut it.

When looking at the Metra harness, it has a black wire, and then the harness that goes into the Kenwood headunit also has a black wire, which is extra long which according to the wiring diagram is the, "Chassis Ground". I'm unsure on whether I splice the two black wires together, or if I am suppose to ground the long black wire to the chassis behind the dash, and not splice it to the other half of the harness at all?

Here's a photo:

View attachment 35147

Some car manufacturers do not include a ground wire within the harness (Nissan) so that's why the black ground wire is a little longer in the head unit's harness, in case you need to bypass the car's harness. In our case we just need to connect the harnesses. Heat shrink tubing works great to make the connections, along with a creme brulle torch.

 

[skrelnik]

Oh, how about the "illumination" wire? Does that get spliced to anything? I ask because there is no color matched wire for it.

You do not need this orange illumination wire to be hooked up. Just leave disconnected and it will all good. Mine is disconnected.

The illumination wire adjusts the brightness of the display panel. If you want your radio's display panel to not be blindingly bright at night, make this connection with the other wires in your harness.

 

[Chris]

You do not need this orange illumination wire to be hooked up. Just leave disconnected and it will all good. Mine is disconnected.

The illumination wire adjusts the brightness of the display panel. If you want your radio's display panel to not be blindingly bright at night, make this connection with the other wires in your harness.

That's the thing though, there's no other wire to connect the orange one too. According to my headunit's manual, there is no illumination wire on it.

 

[skrelnik]

That's the thing though, there's no other wire to connect the orange one too. According to my headunit's manual, there is no illumination wire on it.

Ah, so then the head unit does not require it. I just read your head unit's manual to confirm, and you can tuck the orange wire away, inside an unused slot in the harness. Dimming is built into the head unit, and you can control the times when it activates . Default is 6pm and 6am.

 

[Chris]

Ah, so then the head unit does not require it. I just read your head unit's manual to confirm, and you can tuck the orange wire away, inside an unused slot in the harness. Dimming is built into the head unit, and you can control the times when it activates . Default is 6pm and 6am.

Ahhh, so that's what it is then. They have dimming built-in on a timer... Go figure. I thought I was losing my mind!