NEED HELP Wiring aftermarket head unit

knuckled1

Active Member
#1
I'm not sure how to wire up the navigation, back up camera, or the DVD player. I would like to be able to bypass the parking brake so it works any time, but again, I'm unsure of how to do this correctly.
I will include pictures. I am using the PAC radiopro4 for swc and interface.
1. Illumination (orange)
2. Brake (pink)
3. Battery B+ (yellow)
4. Black (ground)
5. Accessory 12V B+ (red)
6. Reverse (+) (orange)
These are the connections I'm unsure of. I thought there was a vss wire connection as well, but I don't see it now. Please inform me of the correct connections for the above wires. I would also like to know if I should install ground loop isolator or noise suppression, if so, what works best, and where would I install it.
One more thing. In the picture, do the corresponding colors connect together, and then connect or do I have to add pigtails? 20171217_202446.jpg 20171217_202428.jpg 20171217_202428.jpg
 

Reprise

Lifetime VIP Supporter
#2
What make / model HU are you trying to install? Are install instructions online?
I doubt if anyone can tell you what to connect, based on that photo.

As for the parking brake bypass, usually (?) you have to get an adapter that pulses out the +12V feedback signal to fool the HU into thinking the brake is on. You can get them on Amazon or the Bay.
 
#3
No bypass required. Just connect the parking brake wire from the HU to ground. AFAIK, there is no VSS wire. For a ground loop isolator, only way you'll know you need one is if you hear engine whine.
 
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knuckled1

knuckled1

Active Member
#4
I have the instructions, I'm just not sure what is good ground, best accessory power to tap into, isn't real clear, one wire from the interface is labeled vss. Not sure where that goes either. Maybe PAC website has better instrctions, the ones included aren't very detailed,in my opinion. Thank you for your responses and help so far.
 

MRRSM

Lifetime VIP Supporter
#5
Its too bad they did not have just a Basic 19 Pin OBD2 Style Plug like this unit... If I was ever going to consider putting one of these in... it would have to be like this thing... because of concerns about having to deal with a "Bag of Snakes" for all that wiring... especially with wires that should be properly soldered together with a shrink insulator for each and every connection rather than twisted pairing with caps to cover and insulate them...and this one costs only around $50.00:

 

Matt

Silver Supporter
#6
No bypass required. Just connect the parking brake wire from the HU to ground.
Not quite true mate. The new Pioneers won't let you do that any more and do require the micro by-pass for the pulse. I have a now 1 generation older Pioneer that I got new in February that needed it. Apparently the manufacturers have taken the grounding option off the table.
 

Reprise

Lifetime VIP Supporter
#7
My HU is a Pioneer, too - so I don't feel so bad, now. Thanks, mate! :tiphat:
 
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knuckled1

knuckled1

Active Member
#8
The h/u is a dual dvn927bt, I have the directions, and downloaded them. Most of it I get. One of my main concerns is what do I use as accessory power, and what do I use as power to unit, meaning what wire would be best to tap into?
Vss lead is supposed to help navigation, I have no clue what people tap into here either. Is there a vss wire in the vehicle harness?
I also read something about power before the rp4-gm11 or power after, I can't find that info again either. There was a recommended configuration that apparently powered radio with correct voltage. Anyone heard of this.
P.S. I'm a carpenter, not an electrician. I just want to figure our how to correctly wire everything so I don't ruin any components, I am eliminating Bose completely, adding new speakers, an amp to power speakers, and an amp to power the sub/subs, 2 farad capacitor, and back up camera. The h/u supports navigation, and I need to know where do I mount antenna? I've been going thru hundreds of threads, or posts and many are conflicting. There is no start to finish install that i have found similar to what i need to do. Any help, links, diagrams, photos anything might help. Not sure if calling PAC or Dual would make alot of difference?
 
#9
The RP4-GM11 should have instructions on which wires do what. And I have found that most wires are colour coded the same. Accessory power should be identified the same (Red wire on the RP4). I only ever used power coming from the RP4 as this will make it work properly with retained accessory power. VSS is also identified on the RP4 (purple/white wire)
 

DAlastDON

Platinum Supporter
#10
Everything your looking for comes from the GM11. You just have to connect the head units' harness to the GM11 harness. https://pac-audio.com/index.php?controller=attachment&id_attachment=98 has the wire color/designations listed and the head units harness in your picture appears to be labeled by the silver stickers. You do not need to connect the VSS wire in the head units harness. The nav unit uses it when in low/no signal scenarios. Like in a tunnel. The gps antenna, its magnetic, stick it on top of the head unit and forget about it. Or you can put it on the dash or roof. It will work in all three locations.
 
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knuckled1

knuckled1

Active Member
#11
I greatly appreciate everyone's help, I'm pretty clear on everything except the vss wire (purple/white), nothing on harness to connect it to. I thought it would have to connect to the vehicles harness but not sure how to find vss in the harness.
Also, someone had an aftermarket stereo and jumped the red power/accessory, however they used it, to a fat white wire in the harness under the column. Would that be the correct power source? If I remember correctly, when I shut the truck off the stereo shut off and had no accessory power? Sorry to be pain in the ass, this is pretty big task for me, I've never really done installs, I usually had a shop do it. But I love this ltz and I'm gonna get to know it well. So I wanna learn everything I can.
I have the entire interior practically torn out. All removable panels, all speakers are out, the speaker wires are run for the amp, I just have to find the thread where the guy drilled holes in the plastic/boot to run speaker wires in with harness for doors. Where do I drill hole for power wire to go thru firewall? I'm gonna run sub amp off battery, hi's amp off rear distribution under seats. Think that's best way?
 

coolasice

Well-Known Member
#12
I greatly appreciate everyone's help, I'm pretty clear on everything except the vss wire (purple/white), nothing on harness to connect it to. I thought it would have to connect to the vehicles harness but not sure how to find vss in the harness.
Also, someone had an aftermarket stereo and jumped the red power/accessory, however they used it, to a fat white wire in the harness under the column. Would that be the correct power source? If I remember correctly, when I shut the truck off the stereo shut off and had no accessory power? Sorry to be pain in the ass, this is pretty big task for me, I've never really done installs, I usually had a shop do it. But I love this ltz and I'm gonna get to know it well. So I wanna learn everything I can.
I have the entire interior practically torn out. All removable panels, all speakers are out, the speaker wires are run for the amp, I just have to find the thread where the guy drilled holes in the plastic/boot to run speaker wires in with harness for doors. Where do I drill hole for power wire to go thru firewall? I'm gonna run sub amp off battery, hi's amp off rear distribution under seats. Think that's best way?
The vss goes nowhere as your head unit doesn't support it.

Whoever jumped the wire didn't keep their RAP (Retained accessory power keeps radio on when key is shut off until door opens or 10mins has elapsed) option. if you want to use the RAP option return the wiring to original and use the accessory wire provided by the pac module.
 

Reprise

Lifetime VIP Supporter
#13
I'm gonna run sub amp off battery, hi's amp off rear distribution under seats. Think that's best way?
NO! Stay out of the rear distribution block. Period.
You want to run two amps? Both go to the main 12V battery, each with a good fuse / holder of the proper amperage and the proper wire gauge no more than 12" from the positive battery terminal.
So, from the battery 'backward'... + post -> 12" or shorter of same gauge wire -> proper fuse -> wiring to + power terminal of amp. You want one wire segment with no breaks / splices from the fuse holder to the amp. And if you need to have 100A fuse or higher, per the amp install instructions, I would *seriously* consider something like an ANL fused connection (they make 'mini' ones as well, or 'MANL'). Google it, and you'll see what they are.

I just have to find the thread where the guy drilled holes in the plastic/boot to run speaker wires in with harness for doors.
I think it will be a better method to go through the boot, if you can manage it - the boot will help protect that wiring. You can use a coat hanger or stiff wire as a fish tape. The other side in the vehicle end should come out behind the kick panel. If you need to find out how to detach that, stop here and download the shop manuals from our site. Then become a supporting member ('please' and 'thank you' :smile:

Where do I drill hole for power wire to go thru firewall?
You want to find a rubber grommet that already is in use (there's one somewhere, as some of the OEM wiring has to get out to the engine compartment.) Look under the dash for connections that seem to go out of the firewall. If you need a helper to identify from the other end while you two wiggle them, that's fine. Removing the 'knee panel' from underneath the steering wheel will give you a lot more visibility to that area.

Another thing when you run your power and speaker wire - run the power down one side of the vehicle, and the speaker wiring down the other. That will give you the best chance of avoiding a ground loop, as you were asking about before.

Finally, I'm going to say this as kindly and politely as I can - given the questions you've asked so far, and you mentioning that you've had your systems professionally installed before - I would really recommend that you have this one professionally installed, as well, by a good shop that will stand behind their work. Yes, you'll pay - but what you pay for is a good quality job and no electrical problems / gremlins as a result.

There may be other things you can do mechanically to maintain the truck. It's OK to get help with the things that you don't, and to acknowledge when you need that help. It's great to be able to say "I did it myself, and saved a boatload of money". But if you get in over your head, and mess up something in your electrical system, it can be *really* hard to figure out how to undo the damage.

I'll pass on a story from my own younger days...

I had a (new) Honda CRX with three separate amps (one sub, one front stage, one rear), active crossover, TWO Alpine HU - and a crap-ass install job that I did all by myself. For a year or two, I had no trouble with it. Then, one day as I was driving to work, I started smelling an acrid odor. A few seconds later, I was being overcome by smoke - and looking down, I saw my stereo wiring going up in smoke, from back to front. Thankfully, I was able to hang a quick left into a Burger King lot and stop the car - because I was trying to rip out that wiring with my bare hand - WHILE driving, and the car had a manual, as well!

Once in the lot, I got the wiring issue resolved. But my right hand had some pretty bad burns from that wire - if I showed you my palm, you'd see 3 sets of lines going across - second knuckle, third knuckle, palm. It took a few weeks to heal - I remember that - and I was working in a warehouse at the time. Pure misery. My carpet had burn marks in it as well, from the rear to the front. And all because I didn't have the $ to have it installed 'right', and thought that it would be 'easy' to hook everything up. It was fairly easy - but not knowing what I didn't know - you see what happened.

PS: I'm not suggesting or inferring that you're impoverished, as I was at the time. Just showing what 'DIY' can get you...
 

DAlastDON

Platinum Supporter
#17
Thank you, that cleared up quite a bit.
When you say supporting member, how do I go about that?
I think something is wrong with the donation part of the site at this time. But normally you click on you user name in the top right of the webpage the select account upgrades from the column on the right. You can make a donation of any amount or select a gold/silver/platinum membership. Becoming a supporting member gets access to a members only part of the forum and less ads depending on the level of membership.
 
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knuckled1

knuckled1

Active Member
#18
I think something is wrong with the donation part of the site at this time. But normally you click on you user name in the top right of the webpage the select account upgrades from the column on the right. You can make a donation of any amount or select a gold/silver/platinum membership. Becoming a supporting member gets access to a members only part of the forum and less ads depending on the level of membership.
Awesome. After the holiday I will come up with something.
 
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knuckled1

knuckled1

Active Member
#19
i would say the best way to test is to take harness out and try like that if no prob after doing so make sure you got all ur wires right if prob perssist upgrade to a Pac harness axxes is kind of a crappy brand (walmart) also dont hook up the orange wires onthe harnes to the steroe they work in neg polaraty and either mess with ur car or the stereo i would just hook up
yellow
black
red
bluew/white
and all 4 speaker pos and neg
white
grey
green
purple
and that is it
What do white,grey, green and purple hook up to? Also, if I hook back up camera to reverse light at the housings harness, do I still run a power wire to head units orange wire (reverse +) or PAC units green wire (reverse +)???
 

Reprise

Lifetime VIP Supporter
#20
(IMO, I think it would've been better to open a new thread; last activity on this one was almost 4yrs ago. Especially given the 'asap' title in the thread.)

I'm pretty sure white, gray, green & purple are speaker leads (positive / negative; the negative are same color, but have a stripe.) If you have a separate aftermarket amp, you won't use them; you'd hook up a set (or more) of RCA cables, and run new wire from amp to speakers. Metra has the connection instructions on their site. Because I recently d/l'd them to reference something on my own stereo, here's a copy for you...

On the backup cam - if you're connecting power to the cam at the rear, then you should only need to connect to the cam input at the HU - and that is likely via an RCA connection.
 

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knuckled1

knuckled1

Active Member
#21
My apologies. I started a new thread but haven't gotten many responses. I've been searching threads for days, I wish I could actually talk to someone who knows stereos and trailblazers. Thank you for the information, I believe I have the backup camera wired correctly.
Is there a vss wire in our trucks? I need schematics. How would I locate those? Again, thank you for your time.
 

Reprise

Lifetime VIP Supporter
#23
Good thing some unknown administrator combined the posts back. Ignore the attachment, because it's for a Metra harness (which is what the other thread was talking about.

For your VSS - connect that wire on your Dual to the Purple / White wire on the PAC harness. The harness maps out to the correct wire in the truck (that's the purpose of the harness - that plus preserving the OEM wiring from having to be cut.)
 
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coolasice

Well-Known Member
#24
Good thing Mooseman combined the posts back. Ignore the attachment, because it's for a Metra harness (which is what the other thread was talking about.

For your VSS - connect that wire on your Dual to the Purple / White wire on the PAC harness. The harness maps out to the correct wire in the truck (that's the purpose of the harness - that plus preserving the OEM wiring from having to be cut.)
his dual head unit does not support vss... as denoted earlier (post #12)
 

Reprise

Lifetime VIP Supporter
#26
Point taken; correction made.
Logic told me it was him, based on the info I had at hand.
 
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knuckled1

knuckled1

Active Member
#27
his dual head unit does not support vss... as denoted earlier (post #12)
If my head unit doesn't support vss, (which says it helps with navigation, somewhere in a thread i recently read) what powers/controls the navigation part of my h/u?? The data bus connections or rp4?
One more thing, does the rp4 harness acc, power, ground, illumination connected to h/u harness acc, power, ground, illumination need pig tails to connect to sources outside the aforementioned harnesses? Or does databus/ vehicle radio harness cover those connections? I've included pictures, I highlighted what I thought was pigtails in the instructions picture.
Bottom of picture is vehicle harness connection with orange reverse wire, top of picture is radio harness connection with green reverse wire. Do they connect together or just green wire from radio harness to reverse light harness? Or do all the wires I mentioned just connect together with no pigtails. I just don't want ruin anything.
This hopefully is last time I post on this topic. Speakers are all in, wired, door panels back on, rcas, amp turn on,back up camera, power wire for amp, and antenna adapter are all in.
I have taken many pictures. Once everything is done correctly I'd like to make a clear, easy to follow tutorial type write up. Thanks again everybody, you guys are great!
 

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#28
If my head unit doesn't support vss, (which says it helps with navigation, somewhere in a thread i recently read) what powers/controls the navigation part of my h/u?? The data bus connections or rp4?
I don't know your HU but normally, the speed is calculated from the GPS receiver. If your HU has a VSS wire, hook it up to the VSS wire from the RP4. If not, no worries as most don't have one.

One more thing, does the rp4 harness acc, power, ground, illumination connected to h/u harness acc, power, ground, illumination need pig tails to connect to sources outside the aforementioned harnesses? Or does databus/ vehicle radio harness cover those connections? I've included pictures, I highlighted what I thought was pigtails in the instructions picture.
No. I don't know why they show this in the illustration but you don't need any other connections. All the connections you need are supplied by the RP4. You can literally remove the radio with the RP4 and connect it in another truck as-is.

No problem asking questions. That's how we learn :smile:
 
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knuckled1

knuckled1

Active Member
#29
I don't know your HU but normally, the speed is calculated from the GPS receiver. If your HU has a VSS wire, hook it up to the VSS wire from the RP4. If not, no worries as most don't have one.



No. I don't know why they show this in the illustration but you don't need any other connections. All the connections you need are supplied by the RP4. You can literally remove the radio with the RP4 and connect it in another truck as-is.

No problem asking questions. That's how we learn :smile:
Finally. Thank you. That clears up alot. Now if it ever gets above 2 degrees i can finish up.
 

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