Aftermarket Nav Wiring Questions - Help!

[JeepTherapy]

I ended up replacing my head unit with an aftermarket Nav unit (an Eclipse AVN 6610) and so had to get the Metra Axxess VT-GMRC-01 GM Chime adapter. I'm wiring up & connecting the harnesses now, and am 'missing' a couple wires I need help finding in the truck.

 

I've checked the factory radio connector to be sure I wasn't chasing wires I didn't need to, and surprisingly, besides the speaker wires I won't be using, the factory "C1" only had three wires: Radio Class 2 Serial Data, Ground, and +12V. The VT-GMRC-01 'synthesizes' an ignition/accessory +12V switched wire, but I need four more I don't know where to find:

 

1) Illumination: +12V when lighting is on

2) Vehicle Speed Pulse Signal

3) Parking Brake Signal: grounded when parking brake is set

4) Reverse Signal: +12V when vehicle is in reverse

 

What's the best way to find these wires without complete vehicle disassembly? Is there a convenient location for them all?

 

Thanks

 

Jeff Layton

Austin, TX

2005 GMC Sierra 1500 ECSB 2WD

[JeepTherapy]

Can anybody help me find these three wires? That's all that's between me & having tunes back in my truck again.....pleeeeaaaassssssseeeeeee??????

 

 

 

 

I ended up replacing my head unit with an aftermarket Nav unit (an Eclipse AVN 6610) and so had to get the Metra Axxess VT-GMRC-01 GM Chime adapter. I'm wiring up & connecting the harnesses now, and am 'missing' a couple wires I need help finding in the truck.

 

I've checked the factory radio connector to be sure I wasn't chasing wires I didn't need to, and surprisingly, besides the speaker wires I won't be using, the factory "C1" only had three wires: Radio Class 2 Serial Data, Ground, and +12V. The VT-GMRC-01 'synthesizes' an ignition/accessory +12V switched wire, but I need four more I don't know where to find:

 

1) Illumination: +12V when lighting is on

2) Vehicle Speed Pulse Signal

3) Parking Brake Signal: grounded when parking brake is set

4) Reverse Signal: +12V when vehicle is in reverse

 

What's the best way to find these wires without complete vehicle disassembly? Is there a convenient location for them all?

 

Thanks

 

Jeff Layton

Austin, TX

2005 GMC Sierra 1500 ECSB 2WD

[05Quadrasteer]

Wire number 2, I believe I hooked this wire into the +12V you mentioned that you are not currently using on the original connector.

 

Wire number 2, I don't recall hooking anything up to that one when I installed my new headunit. It sounds like it is the one that auto adjusts your volumn for you if you have the orginal headunit. Since I have never found an after market headunit that works with it then would have to assume it is not necessary.

 

Wire number 3, just hook it up to any metal surface to create a ground. This one is used by the navigation system. If hooked into the parking brake it provides the ground so that you can adjust navigation settings. So you hook it to any other ground and you can make any changes while driving instead of while parked with the parking brake set.

 

Wire number 4, unless you have a backup camera don't worry about it.

 

Hope you find these words a bit helpful. Shout back if you need any more help.

 

Have a nice day.

 

Bill

[JeepTherapy]

Thanks for the help, Bill. I've also done a lot of searching of the archives and my service manual. I'm almost done - just a couple more questions.

 

You listed two "Wire number 2's" - can you clarify?

 

I found the following:

 

1) Illumination: +12V when lighting is on

Back of headlight switch. Pink wire, location 7 (bottom left corner)

 

This isn't the 12V ignition or 12V hot - this is only supposed to be on when the dash lights are on. Doesn't appear to be the dimmer wire, but the illumination wire. I guess this simply dims the display at night?

 

2) Vehicle Speed Pulse Signal

Back of gauge cluster. Green with white stripe.

It is pin A4(4th from the end)

 

I don't know if this is a volume adjustment (Eclipse AVN6610) or if it's a navigational aide when the GPS signal is blocked. Either way, it's on the back of the instrument cluster - shouldn't be too hard to find.

 

3) Parking Brake Signal: grounded when parking brake is set

L-BU – one wire on Parking Brake Switch

OR- your idea (which I like)

Hook it to any other ground and you can make any changes while driving instead of while parked with the parking brake set.

 

I have an Eclipse Nav head unit. If I can get away with simply grounding this wire & everything will be 'happy', I'm all for that.

 

4) Reverse Signal: +12V when vehicle is in reverse

Found this on another post:

beneath the steering column. you will have to take off the cover below the steering column. balck harness, and i think its the light blue wire

 

I am not installing a BU camera at this time. If I can blow this off, then I'm good!

 

Let me know about the above - your help is much appreciated.

 

Wire number 2, I believe I hooked this wire into the +12V you mentioned that you are not currently using on the original connector.

 

Wire number 2, I don't recall hooking anything up to that one when I installed my new headunit. It sounds like it is the one that auto adjusts your volumn for you if you have the orginal headunit. Since I have never found an after market headunit that works with it then would have to assume it is not necessary.

 

Wire number 3, just hook it up to any metal surface to create a ground. This one is used by the navigation system. If hooked into the parking brake it provides the ground so that you can adjust navigation settings. So you hook it to any other ground and you can make any changes while driving instead of while parked with the parking brake set.

 

Wire number 4, unless you have a backup camera don't worry about it.

 

Hope you find these words a bit helpful. Shout back if you need any more help.

 

Have a nice day.

 

Bill

[05Quadrasteer]

The first mention of Wire 2 was supposed to be Wire 1.

 

Have a nice day.

 

 

Bill