Audio Receiver Install

I’m running into issues installing an Alpine receiver into my ‘03. The truck has an old school aftermarket head unit that I’m looking to upgrade. The factory amp was already unplugged from the previous install and is just sitting there. For the upgrade I purchased the receiver and the recommended wiring harness from Crutchfield. After I make all the connections I’m getting no power to the receiver. I’ve verified there’s no blown fuses. At the splices (connection between new wiring harness and receiver harness) I’m getting 12V at the Constant (Yellow) wire but not at the Accessory (Red). For the Red it starts at 0.1-0.3V but then drops to around 0.01-.02V. I remove the new wiring harness and verified I’m getting 12V coming out of the factory wiring harness. So, somehow the power is going through the factory harness but not through the new wiring harness. I’ve actually tried 3 wiring harnesses so I know it’s not a wiring harness issue. Also, the old school head unit worked just fine before. Any thoughts?

 

You didn't mention what make/model/year of truck you have and how many speakers it has, 4 or 6. That info is helpful so we know what you're dealing with, and where the factory amp would be located.

You also didn't give any pics of the wiring connections for the harness, which may help us to spot something wrong. That would be really helpful. Could be helpful to see the harness at the factory amp too, just to understand how that was bypassed previously, I've seen some real mangle jobs.

Without seeing pics of the wiring, it would be tough for me to say. I've never heard of a similar issue, and I've been doing this stuff for decades now.

Only thing that makes sense to me is to (1) check the factory harness to make sure the ACC PWR pin isn't sheared, cracked, bent or otherwise damaged and (2) backtrace on whatever the last person did on the prior radio install to nix the amp out of the pic, making sure they didn't do something really f'ing stupid with the power/ground that was previously feeding the factory amp.

 

Have to plug the center stack AC controls back in to get power to the harness I believe. If you are testing it with the AC controls unplugged, it won’t power up.

 

Official welcome for your first post... Any pics?

 

My bad! I have a 2003 Tundra SR5 that I received after my father-in-law who passed a few years ago. The truck was mostly a chore truck while I commuted in another vehicle and I'm finally getting around to doing some things to it.

The issue was fixed by knabores recommendation to simply plug the AC controls back in.

So, now the next question is how to go around the parking brake issue? The Alpine unit needs to read the parking brake is engage in order to access settings like bluetooth setup and others. I attempted to run the unit for the receiver straight to the ground but it only works when you take the wire on and off again. If you tie it up, turn the vehicle off and turn back on it won't work. You'd have to remove and reattach to ground. I've read others tying in a toggle switch. Is this the best/most efficient work around?

Oh and thanks for the welcome! I'll post some pics when I get the vomit of wire out of the way from this project.

 

Toggle switch for that allows you to manually do the function you describe. Pioneer units I have wired up have a small adapter you can wire in to defeat the park feature. Bought one on Amazon.

 

I used this on my brothers alpine touchscreen on his veedub. Works great.

https://youtu.be/TpQUKdfED34

 

@Diddlytopper this is also what I used. Super easy setup. I think I grounded it to a screw for the dash, rather than splicing into anything? Or I might've spliced at the harness join. I forget, but it worked great. I'm running an Alpine iLX-W650 and used this specific part:

https://www.amazon.com/gp/product/B006FKAHFM/

 

W650 here also. Easy peasy and works great.

 

I used that bypass when I had Pioneer HUs.
One of those HUs, it would give me an error message maybe once in every 75 starts.
Turn off and restart it would go away so I dealt with it.

The Kenwood is much easier..
You just ground the brake wire to the HU chassis..

How to do the parking brake bypass on your new Kenwood radio - YouTube


Glad you got it figured out @Diddlytopper
Welcome to the forum..

 

Yep, Kenwood in my 05 DC. Cut the wire down to like 3 inches, put a ring terminal on it and ground it to a screw on the back of the chassis. Easy peasy lemon squeezy.

 

Thank you everyone for the replies! I installed the bypass linked by Shifty and all works as advertised. Cheap and easy workaround. Thank you!