Hi, received a navigation system for fathers day and soon will be putting in the 1994 coupe. I find a PAC interface for the 97 and up cars but cannot find anything for the C4 cars. would someone be able to post or email me a list (and part numbers if possible or website ) of the connection interface items I will need so I can gather for the install. The navigation unit is not a high end unit but should suffice for my causal driving needs.

Thanks in advance.
Tom

 

Here's what I was able to find for your car. https://catalog.pac-audio.com/?fc=mo...m=1866&submit=

 

Wow, thank you for the quick reply.. would you know if these devices are pretty self explanatory for installing, I am able to follow generally but with some eyesight issues and age I would not want to get into a situation of the car apart. did a search but other than some references to DOUBLE DIN Mods,(not on here anymore I see) I have not seen of found and write up for the C4, even the youtube does not have much other than completed or partial views but no real directions.

Any added help would be appreciated as I gather items needed. from your link, it looks like that device is ALL I WOULD NEED ???
THANKS TOM

 

Here's what looks like a pretty good video for you, I can't really answer any questions you may have concerning though as all my experience is with with the C6's.

 

This looks like the installation mount needed for your car also. https://pdf.crutchfieldonline.com/Im.../120993051.PDF

 

I suggest you also post your specific questions in the General Question C4 section of this forum. Like I mentioned, my experience is with the C6's, though I have done many installs on older cars over the years, just never a C4 Vette. I'd imagine there's someone in the C4 section that has done an install similar to what you want to do who may not visit the Audio/Electronics section to see your thread, who could answer your specific questions better than I could.

 

I thank you for your assistance and will follow up on you suggestions as well as the video.

 

I watched the video and it was most helpful, Thank you for the link. One question I have and will go look in the car, someone said the removed radio where the nav system will go is only a controller and the radio is actually behind the passenger so I need to go check that in the next day or so while I still gather items.

THANK YOU,
Tom

 

Yeah, can't help you there with your question.

 

I did a couple of audio installs in 96s many years ago. Please tell us about your car. Bose or standard factory audio system? Manual or automatic A/C?

 

Good Morning, the car is a 94 coupe, 6 spd, factory Bose, automatic A/C , and not a daily driver. Received a Navigation system as gift from family to kind of update driving the car and not have items cluttering the dash. as a senior it's getting hard enough to get around.and would be good to not deal with floating items.
Anyway, we have the radio removed and looking to gather all the items, wires, connectors etc. to install it.
It is not a unit with the CD/DVD, just basic radio, blue tooth, navigation, GPS etc and not an expensive one either.
Any help guidance in doing the connections would be helpful. It looks like from the video Madsonp linked me that because the unit I have is not very deep due to not having the CD/DVD I will just have to play with centering it and maybe trimming the plastic some for the trim to fit over the face area.
I plan on running the speaker wires along the transmission tunnel (I think) back to the area behind the passenger seat and if I understand that is where all the real connections are made. Leaving the bose in place as it all has worked but unclear as to using the original radio harness plugs( ???) or just taping them up. Making the connections is our issue. this week I will remove the passenger seat to be able to hide the wire bundle under the transmission tunnel carpet and figure out how to neatly get it into the rear compartment. I am not very agile now being in the mid 70's so only due little by little items at a time.
So, that is where I am at right now.....have the unit it is 6.88" wide, 3.93:" high and less than 4 " deep (off ebay, link is https://www.ebay.com/itm/Android-8-1...72.m2749.l2649.
it will hopefully meet my driving needs so any help with the wire connection will be appreciated, I have ordered the OEM PAC adapter so all I am getting ready to making access this week. can't stay out in the Fla. Heat like I use to so it will take me awhile to do the install. Again, the original harness plugs in the dash are my initial concerns on using, pinning out correctly and from the pics in the link any other suggestion you can provide. Its not a high end unit, and I do not want to alter the dash as the car is original and our intent is to just provide new dash unit, operating ok. Later, tom

 

First, let me give you some basics. As you guessed, the head unit in your car is basically a remote control unit for the actual tuner module in the passenger side storage bin. Once you remove the factory head unit, the factory tuner module can no longer function and will also need to be removed. The connectors that plug into the tuner module are what you will use. All connections (except illumination) need to be run from the new stereo to the passenger side storage bin. You should only use the illumination wire in the factory head unit harness. The other wires in the factory head unit connectors are very small, low current and should not be used.

Being that you have the C68 automatic A/C, you should not have the "sys" error display in the dash.

I am not familiar with the PAC module. It *appears* that the PAC connector would plug into the connectors that were plugged into the tuner module, which makes sense. If so, you will need to run your own wiring and antenna extension cable from the PAC in the rear passenger storage bin to the new head unit. Looks like it has audio level adjustments, which is nice.

The wiring kit I used in the past was the Metra 70-1857:

https://www.crutchfield.com/p_120701...s-Harness.html
https://pdf.crutchfieldonline.com/Im.../120701857.PDF

This kit has the wiring all in a bundle. A few of issues with it is that the audio levels are not adjustable as is the PAC kit you ordered, and also it is very long because it is also used on some Cadillacs where the tuner module is way back in the trunk. Since you can remove the tuner module, you could just roll up the extra length of cable in the storage bin. Lastly, you will need to tap into the small wire in the factory head unit connector for the illumination circuit in order that your new stereo will dim the screen when your lights are turned on.

 

Sir, THANK YOU for the reply and explanation. If I understand correctly, the tuner in the dash and the item behind the psngr seat both get removed,
run wires out of the new Nav unit to the psngr well, using the pac unit interface to plug into the existing plugs taken off the psngr module.
I need to find the illumination pin in the dash harness, tap into it and attach to the new Nav illumination wire.
will be removing seat and tunnel tomorrow.

Just for clarity, I am only using one wire under the dash harness for illumination by taping into it, all other wires in those two harness plugs DO NOT GET USED.
CORRECT. (why....because they are less than the normal 12v and driven by some other device/pc/module)
TOM

 

1. Sounds right.
2. Not voltage, but current. Those small factory wires at the head unit are not meant to handle much of a load. The big wires are in the passenger side bin.

 

Thanks for jumping in there Klaus, I'm just gonna sit back, eat some popcorn and watch how things turn out.

 

One other thing I would say is you might want to wire all this together and test it before mounting the head unit and trimming things. Connecting an aftermarket head unit to a 25 year old factory Bose system may not work out, and you don't want to trim/modify anything permanent in the car until you are satisfied this combination will work to your satisfaction. That way if you are not happy with the new combination you can always go back to stock, provided it was working.

 

You and Madsonp make good points and I appreciate it. I was out in the heated garage for awhile today. I could not attach two photos but provided the links relating to my questions here, but they are the small wire assemblies that come with the unit and plugs into the back. now I see it has all the speaker +- wires, parking, B+, acc, key1, key2, Ground, illumination, think thats all of them. They are maybe 22 or 24 ga wire ??.
My question is do I find wire the same size wires at a radio shack and solder splice them on the navigation plug end, run them to the pac plug and similarly solder them to it in corresponding colors....or do I just use the ones to power up the Navigation Unit at the dash with appropriate wires, what is Key 1 and Key 2 used for, and I got this relocation Metra 70-1857 harness https://www.ebay.com/itm/Metra-70-18...72.m2749.l2649 and use that on the outputs of the Navigation to the Pac unit and plug the appropriate plugs into it from the car harness plugs in the psgnr well.. Please know I may seem to be asking the same questions over again but trying to have as clear a process as possible and I am currently writing down into a step by step sequence to attempt to follow.
if I am using the Metra harness and not the small gage wires for the speakers, then the harness seems to be making the install easy. (relatively speaking) and with limited solder that would have potential faults. Since I do not have the Pac roem-gm21 here yet.....https://www.ebay.com/itm/PAC-ROEM-GM...72.m2749.l2649 I will probably have more questions as I layout the items on the floor prior to install. Another question would be, since the dash and other unit are not in anymore, am I correct that somehow the unit removed from the back well gets harness power from those plugs thru the Key On circuits into the Pac interface, and that Pac unit handles the BOSE portions.

Q. bench testing the unit prior to actual install with all the wires in place and appropriate jumpers from the car to the wired, pre installed assembly should not cause any harness/backfeed issues and if the wires all were done properly then the unit can be cycled, speakers adjusted, balanced without any concerns. Klaus, as you mentioned the car is 25 yrs old with original wires, hoping to keep it that way!

Well, lying here resting from the heat caused me to come up with these questions, about all I know of Audio is if I can't hear it too well, I turn up the volume.
Later Tom

 

I don't believe you could use the Metra 70-1857 along with the PAC module. It would be one or the other as the Metra 70-1857 is for Bose and comes with RCA jacks for the audio to connect to the new stereo.

Key 1 and Key 2 are for use with steering wheel controls. Not used for your car.

Yes, if you build your own harness you will need the primary wire and the antenna extension.

I recommend you wait until your PAC unit gets there and you see where it will plug in. *IF* the PAC plugs in to the connectors in the passenger bin, then you would know the wiring needs to go from the new stereo to the passenger bin, and connect to the PAC. *IF* this is the case, and you don't want to built your own harness, then you could buy the Metra 70-1856, which is for the non-Bose cars. One end would connect to the head unit, then the other end would connect to the PAC unit. The difference between the Metra 70-1857 (Bose) and the Metra 70-1856 (non-Bose) is that the 1857 uses RCA jacks, and the 1856 uses plain speaker wires. Both include the antenna cable extension you would need.

So, you have at least 3 options.

1. Use the PAC module you purchased and make your own wiring harness. You will need an antenna extension cable, as the factory antenna cable plugs into the factory tuner module in the passenger bin. I have no experience with the PAC module, so I hope it will work.

2. Same as #1, but buy the Metra 70-1856 non-Bose harness instead of building your own harness. You would cut the wiring plug off of the 70-1856 that would normally plug into the car wiring in the bin, and solder the wires on the PAC. Again, I have no knowledge of the PAC module for this car, so I am making assumptions based off of pictures. WARNING - DO NOT CUT THE ANTENNA EXTENSION CABLE. DO NOT CUT ANY WIRES OR CONNECTORS FROM THE CAR WIRING.

3. Purchase the Metra 70-1857 (Bose) and just use it, not using the PAC. This is the only option I have used.

There are many more variables. For example, who knows what the voltage level outputs are for the RCA line outs on your new stereo? Since the Metra 70-1857 uses the RCA jacks, will the volume match up? No adjustment with this setup.

I am assuming from the pictures that the PAC unit uses the speaker outputs from the new stereo, then you adjust the output level with the 4 adjustments on the top of the PAC to make it loud enough without too much distortion.

All this to say car audio can be very hit and miss, especially when mixing and matching a factory Bose setup with an aftermarket stereo. There are many people here that started out like you, got frustrated, then ripped out all the factory speakers and amps and installed a complete system from scratch. Keep your options open in case this setup does not sound good or if you have issues with your Android stereo. Until you start cutting, you can always go back to stock.

 

Good Evening, appreciate the replys, question is confusing to me. we thought the GM-21 package substituted control for the Bose system (speakers) in lieu of the OEM equipment. Also, we also thought that the Metra 1857 was for keeping the BOSE capability (again, audio is not an area I have much understanding of with cars in terms of mods/installs) and with the RCA jacks just appears to make the install less confusing and straight foreword with minimal wire connecting.

since you have delt with the C4's, would you by chance know the pins & connector in the dash area that I unplugged that I will need for the B+ power/ground/illumination taps.(am I correct as far as tapping from the harness) or are there other areas in the fuse panels or other modules you recommend getting those sources from.

parts wont be in till next week so remainder of this week I will work on the seat removal and tunnel carpet removal in preparation. looking with the passenger seat back forward do you have any suggestions on how to get the wire bundles neatly into the well, my first thought is to drill a hole, rubber grommet, seat with sealant but unsure of height from floor or other dimensions that you might suggest. I would like to transition it front to rear as neat/hidden as possible.

again, thanks for the communication replys, will get back with you after the weekend.

Later, Tom

 

While waiting on the PAC interface, might I suggest you look through the manual to get an idea how to wire it up https://pdf.crutchfieldonline.com/Im...41/541GM21.PDF I know, I know, get back to my popcorn.