C4 Suke

Hi, I am going to install a Jensen cdh900 head unit soon and I noticed the connecter it came with has open ends so it looks I'll have to do some splicing. I would rather not do that, and just hook it up to a harness, so I am thinking maybe Jensen sells a harness that directly fits GM harness, but I can't find this anywhere.

But, the JVC that was previous installed has a harness that fits GM, so I am thinking about splicing the Jensen wires to the JVC harness, that way I won't splice up any of the stock wiring.

Is this a good idea? How else can I go about doing this? Thanks!

Suke

junkyarddog

lol, sorry I'm not laughing at you....it's just that I think you already have a GM wiring harness!

if you have a bundle of wires which connects the HU and the other end fits over the factory plug, then it may be that someone has already used a harness. Just chop it in half and splice the wires, match the colors.

TIP: GMs factory wiring stinks....I recomend grounding the HU to the frame behind or under the radio (any place which doesn't penetrate through the floor is best, unless you can prevent the rust underneath)

Run the Batt + from the fuse panel or even from the battery (be sure to fuse at the battery)

Everything else can be used with the harness with little trouble.

TIP 2: if you aren't soldering, pigtail the copper and crimp both at once, double ended butt splices can be used without using both sides...it's also a convenient way to test anything later and/or add wiring. Most importantly, it makes a better connection.

C4 Suke

"if you have a bundle of wires which connects the HU and the other end fits over the factory plug, then it may be that someone has already used a harness. Just chop it in half and splice the wires, match the colors. "

Yeah thats the situation, I am going to try to do just that. Thanks for the tips.

C4 Suke

Well I spliced the 2 harnesses together, only to find out that it doesn't work, and that it was never the head unit in the first place, but the GM wiring OR the JVC harness, so I'll be going back to the better JVC, but now I am trying to find out where the problem is.

Here is what happens: When I hook up the stock stereo, I only get sound from the left front speaker. So I thought the stock stereo was bad as well.

Then today I spliced up the harnesses and connected it to the gm harness, and no sound, same symptoms the JVC was experiencing.

This is a 1990 so it has the 3 wiring harnesses that go into the stock radio. These 3 go into the aftermarket adapter/harness, I'll try to get pics later. But when I took out the WHITE harness, I started getting sound on the left front again. So I placed the white harness in slowly but not completely, and I got sound coming from the right rear speaker as well. SO, since both my stock radio and this harness are having problems, I'm concluding that this has to be the stock GM wiring.

What do you guys think? The stock harness? I didn't want to hack up the stock wiring, but it seems as if that is the only option left. Maybe I'll have to cut up the stock and splice it to another stock harness to make things easier, I'm sure the junk yard wouldn't charge me for something as small as that.

DISTURBthePEACE

take a decent pic of your wiring and I might be able to help you from there. I need to see your wires from the jvc and also the factory wires. it sounds like you might have some wires backwards or somethin...all the speakers worked before though, right?

C4 Suke

I'll get some pics tomorrow, nothing worked in the first place when I bought the car, thats why I pulled the head unit and bought a new one and spliced the harnesses of old Head unit and new one so I can directly connect to GM wiring w/o cutting up the GM wires.

junkyarddog

Save alot of headache and leave that harness alone.

Just rewire from scratch. Run new speaker wires, just undo the grills and fish the wire from the bottom or srop it down from the top. Fish it through the rear panels too because those can be a pain to remove if you've never done it before.

If you have a multimeter, you can test the speaker pairs and see if you have 10 ohms (factory gm speakers) yup 10 ohms....a good reason to replace with 4 ohm aftermarkets!

Do it nice and you'll never have to do it twice! Be sure to disconnect the factory wiring at the speakers too.

Seriously, I could have most cars wired in 20-30 minutes. If you were good with troubleshooting and had a multimeter to use, it might not be the most practial thing to do, but this way gaurantees your radio will work. Good luck!

C4 Suke

Here are the pics:

this is the GM wiring harness for my 1990 IROC: It consists of 3 harnesses that go into the stock stereo:


The following two pictures are those of the harness which allows me to connect the JVC head unit to the stock wiring:





I have gave re-wiring it a thought, I might do that as a last resort, because it seems kind of hard, I don't know how I'd get wires to the speakers.

junkyarddog

Looks like you'll need this:

1982-87 Pontiac Firebird Stereo Information
Constant 12V+ Orange
Switched 12V+ Yellow
Ground Black
Illumination Gray
Dimmer Brown
Antenna Trigger Pink
Antenna Right Front
Front Speakers 4" x 6" Dash
Left Front (+) Tan
Left Front (-) Gray
Right Front (+) Light Green
Right Front (-) Dark Green
Rear Speakers 6" x 9" Side Panels
Left Rear (+) Brown
Left Rear (-) Yellow
Right Rear (+) Dark Blue
Right Rear (-) Light Blue


these colors don't change much so everyone here is welcome to use this info.

If you're doing an alarm or just need ACC (12v with ignition) for the radio:

1982-87 Pontiac Firebird Security Information
Constant 12V+ Red Ignition Switch Harness
Starter Yellow Ignition Switch Harness
Ignition Pink Ignition Switch Harness
Accessory Orange Ignition Switch Harness
Tach White Coil
Brake Switch White Brake Switch
Trunk Pin White (-) Cargo Compartment Light
Parking Lights Brown Light Switch
Head Lamp Yellow Light Switch
Hood Pin n/a
Factory Disarm n/a
Door Trigger White (-) Driver's Pin Switch
Door Lock Light Blue Driver's Kick Panel
Door Unlock Black Positive Trigger
Horn Wire Black (-) Steering Column

junkyarddog

check for power, check for sound, just a few wires at a time. That's the best you can do without a DMM.

C4 Suke

Thanks for the info, so you suppose it is the GM harnesses? I just connected the factory stereo, and I did the same thing as before, put the harness in half way instead fully, to get the back right speaker to work. I can only get the front left and back right speakers to work.

But I was wrong about it being the white harness, I actually meant the blue harness. Who knows might be both, since one harness is for front speakers and other is for rear, I dont know what would cause both to go wrong.

I am going to rewire one of the speakers to see how hard of a job it is, will I have to remove the carpet?

junkyarddog

look at the pins, are they bent, pushed back, loose, corroded?

you can release the pin(s) from either harness carefully with pliers or small screwdriver.

try some contact cleaner (De-Oxit 05) is my favorite.

Just run new wire and leave that harness alone. Leave it disconnected and just run wiring directly to the pigtails on your HU (loose wires)

before you go through the trouble, try to cut into the wire without cutting any of the strands, just 'skin' the insulation back in the center, an inch or two away from the harness, expose about 1/4" of copper, splice each speaker into it just to see if it is good, if so, solder it up, tape it and leave it, no wire running necessary.

I do not recomend those EZ taps or whatever they're called, in my experience they need to fit just right or else they don't make contact or they cut the wire when you crimp it.

If you don't have anything good to cut the wire with, use a sharp knife (cautiously) or get yourself some 'mechanical wire strippers'. I got a nice pair for $5 at home depot, any good electronics store (not Radio Shack) has these too. Worth thier wieght in gold when it comes to wiring.