Head unit wiring

[jpau00]

I am trying to install a new head unit in my 1987 Econoline. I pulled the old, non-functioning radio a while ago. It didn’t have a harness connected just the speaker wires. I went into the space more closely and discovered a few things.

1) The wiring harness was not attached to anything on the radio or the van. The only wire connected was the ground wire. It looks like someone started setting up a wiring harness and gave up quickly.

2) The speaker wires and a red wire were there as well. I assumed someone tried to get constant power to the old radio, but it turns out the wire was cut further down under the dash.
(There’s a whole mess of wires in the driver side foot-well).

So basically I need to start over with the wiring. I am wondering if anyone on the forum has some experience with this.

The main wiring I need to do is...
1) Constant power
2) Switched power
3) Dimmer

I am thinking of splicing into the interior fuse box. For the switched power, I can tap into the accessory fuse.

For the constant power, all of the fuses are more than 10amps, which is recommended for the radio. I am thinking of tapping into one of the incoming wires and adding an inline fuse.

I also have a constant power wire that goes directly to the battery I made for a 12v/usb charger I keep on my console. That wire is 14 gauge though, and I don’t think I should downsize the wire coming off of it.

Finally there is the dimmer wire, and I have no idea where to connect that.

Would love any suggestions or insights, even if it is just to pay a stereo installer.

[BrianW]

Hoo boy, that’s going to be fun! [emoji15] I’m sure some deep google work will turn up the wiring harness colors for the stereo. Even though you don’t have the harness at least that should get you started.

When you say “constant power” do you mean for the unswitched memory maintenance wire? Usually that’s less than 1 amp on modern head units (maybe .5, I can’t recall) just to keep basic memory stuff alive.

[jpau00]

Yes. The constant power is for radio memory. Actually the radio has a fuse, so I probably don't need an inline one. I'm going to pull the dash apart today and try to hunt down those wires. I can't imagine the PO would have fully removed them, given the massive amount of random extra wires throughout the van.



I've been hunting through youtube videos. Everyone is already starting with wires, even if they have to wire up a new harness. Occasionally someone will make a breif reference to tapping into the accessory wire in the steering wheel column or the headlights for the dimmer switch. That's a little more than I want to get into, which is why I was hoping to use the fuse box. If you have a blade style fuse box, there are these cool little pigtails you can use, but mine is of course the tube style.

[BrianW]

Wiring colors for your van:

https://www.the12volt.com/installbay...etail/828.html

I’d highly suggest trying to use the OEM power, etc, wiring if you can rather than running new power wires (unless you need high-draw wiring like for an amp).

[gahamby]

"Finally there is the dimmer wire, and I have no idea where to connect that."

The dimmer wire from the head unit, in my experience, connects to the load side of the dash lights dimmer.

[jpau00]

Originally Posted by BrianW

Wiring colors for your van:

https://www.the12volt.com/installbay...etail/828.html

I’d highly suggest trying to use the OEM power, etc, wiring if you can rather than running new power wires (unless you need high-draw wiring like for an amp).

Thanks! That is a super helpful link.

[jpau00]

Originally Posted by gahamby

"Finally there is the dimmer wire, and I have no idea where to connect that."

The dimmer wire from the head unit, in my experience, connects to the load side of the dash lights dimmer.

That makes sense. I'll try that tomorrow