Tap into timed power off factory circuit?

[haus3452]

So, I installed a Pioneer aftermarket head unit in my new-to-me 2003 Chevy Venture a couple weeks ago. Long story short, I had to run a fuse tap for the accessory wire because there was no compatible accessory wire in the factory harness.

The factory radio stayed on for approximately 10 minutes after the ignition was off, as do the power windows (and maybe more things I'm not aware of). I fuse tapped the rear wiper because it's on when the key is on and turned backward to the accessory setting. However, the Pioneer doesn't stay on for 10 minutes after the ignition is turned off, as the factory radio did (and the power windows do). I'd like for my Pioneer to do so. What is the switch/relay/whatever timed mechanism that gives certain things power after the ignition is off called? And where can I find it to either tap into it, or tap into one of the wires that come out of it? How would you suggest going about wiring my stereo into it?

I have a Haynes manual which has the wiring diagrams in it, but I'm finding nothing that sounds or looks like it might be what I'm looking for. Any suggestions would be welcomed and appreciated! Thanks on advance!

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[XTR]

It's called Retained Accessory Power (RAP) and I can't help you anymore than that.

 

[keep_hope_alive Premium Member]

So, I installed a Pioneer aftermarket head unit in my new-to-me 2003 Chevy Venture a couple weeks ago. Long story short, I had to run a fuse tap for the accessory wire because there was no compatible accessory wire in the factory harness.

easy solution, install the GMOS-04 adapter which generates the turn-on signal that arrives over GM's Class II Data Bus.

This also retains safety chimes and other features inherent in the factory radio.

GMOS-04 [GMOS-04] Axxess Integrate, Comprehensive Interface Products

 

[haus3452]

It's not really worth $77 to me to have retained accessory power. Plus, my van doesn't have OnStar nor a factory amplifier, which it seems is the main draw to the GMOS-04. And... Looking at it, I wouldn't know how to install it. My car audio knowledge doesn't go much past wiring in a harness to plug into the factory plug, or, the way I originally learned it, cutting the factory harness off and wiring the stereo straight in. I appreciate the feedback though.

I'm hoping to move the accessory wire to tap into the RAP circuit. I read on a couple pages after doing a Google search of a couple people who had done it successfully, but I haven't had the time to sit down and study those pages yet. If/when I figure it out I'll post the solution here.

Until then, if anyone else has any words of wisdom, please chime in.

 

[jco1385 5,000+ posts]

Edit:

Here's the power distribution diagram for the relay:

 

[haus3452]

I don't know where you found that diagram, but that's awesome!!! Thank you!!!

Question... it looks the RAP relay is connected to the ignition switch, and then goes to the window fuses. I ran a proper fuse tap and used the rear windshield wiper slot for my accessory wire. If I would use the power window fuse instead, would should that give my radio RAP too?

 

[keep_hope_alive Premium Member]

It's not really worth $77 to me to have retained accessory power. Plus, my van doesn't have OnStar nor a factory amplifier, which it seems is the main draw to the GMOS-04. And... Looking at it, I wouldn't know how to install it. My car audio knowledge doesn't go much past wiring in a harness to plug into the factory plug, or, the way I originally learned it, cutting the factory harness off and wiring the stereo straight in. I appreciate the feedback though.

The main reason isn't OnStar (few use it). The reason for the GMOS is for an aftermarket HU ignition source, retention of safety chimes, and other safety related items. It also helps with parking brake, VSS, speed sensors, etc. for navigation systems. Simply put, a GMOS translates all of the digital information shared with the head unit. Consider how an insurance company would view deliberate deletion of safety items as an excuse to avoid a payout. Consider that the vehicle should not be sold without factory safety items. Omitting the GMOS is similar (legally) to removing lamps in the dash to say airbags aren't working or seat belts aren't fastened. Installation of the GMOS is not harder than a head unit.

From the diagram below, you can test the function of RAP on the two fuses and add-a-fuse there. test with a DMM to verify they do what you want.

Bonus Info: you can generate RAP in any vehicle with a few relays

Negative Door Trigger:

http://images.the12volt.com/12voltimages/raddelay3.gif

How to Wire Relays - Radio On Until Door Opened (Retained Accessory Power) - Negative Door Trigger

Positive Door Trigger:

http://www.the12volt.com/installbay/uploads/radio-on-positive_door_trigger.gif

How to Wire Relays - Radio On Until Door Opened (Retained Accessory Power) - Positive Door Trigger

 

[AFS585]

The main reason isn't OnStar (few use it). The reason for the GMOS is for an aftermarket HU ignition source, retention of safety chimes, and other safety related items. It also helps with parking brake, VSS, speed sensors, etc. for navigation systems. Simply put, a GMOS translates all of the digital information shared with the head unit. Consider how an insurance company would view deliberate deletion of safety items as an excuse to avoid a payout. Consider that the vehicle should not be sold without factory safety items. Omitting the GMOS is similar (legally) to removing lamps in the dash to say airbags aren't working or seat belts aren't fastened. Installation of the GMOS is not harder than a head unit.

From the diagram below, you can test the function of RAP on the two fuses and add-a-fuse there. test with a DMM to verify they do what you want.

Bonus Info: you can generate RAP in any vehicle with a few relays

Negative Door Trigger:

http://images.the12volt.com/12voltimages/raddelay3.gif

How to Wire Relays - Radio On Until Door Opened (Retained Accessory Power) - Negative Door Trigger

Positive Door Trigger:

http://www.the12volt.com/installbay/uploads/radio-on-positive_door_trigger.gif

How to Wire Relays - Radio On Until Door Opened (Retained Accessory Power) - Positive Door Trigger

this. to the OP, a PAC C2R-GM24 or it's replacement, the RP3-GM11 may be cheaper than the metra GMOS and will do the same thing. the proper harness is definitely the best way to install radios into vehicles that have RAP.

 

[haus3452]

So, I tried moving the add a fuse to the rear vent window fuse and it worked to give the stereo RAP! Thank you again for the diagram!

As far as the GMOS... I honestly haven't noticed any change in safety signals or anything else since installing the stereo. Not to say that there wasn't some effect, I just didn't notice any. If I decided to sell it, I'd put the factory stereo back in and keep the after market stereo for my next car. Although, I will check out the other company's version of GMOS that was mentioned. Thank you all for your advice!