'89 speaker wireing

[ojh]

I recently bought an '89 and pulled the radio/cassette player to upgrade with an aftermarket CD player/receiver. The color codes going to the speakers are very different from what the schematics show, when i try to read out the speakers the ohm readings indicate shorts between everything and i cannot get the speakers to work proper. I pulled the drivers door panel to look at that speaker and it has a different color code as yet - although simliar to the schematics. It is as if there is another device between the speakers and the harness going to the original radio/cassette.
The sticker on the door says this Grand Marque was made in Canada, if that makes any difference.
I want to get to the original speaker wires, where will i find them?
Thanks oj

[miamibob]

If it is a "Premium System" it also has a factory amp and that may be throwing you off. Bobby

[jaywish]

What schematics?

[tjc78]

Are the connectors behind the radio both rectangles or is one square? If the latter you need the premium sound harness and Amp Bypass Cable for the amp (which is located in the passenger side trunk area on the rear seat back frame). This will make it super easy with no cutting of the factory harness.

Checkout Crutchfield's website, they will spell it out for you once you enter the year, make and model of your car.

[HiFiMerc]

I want to say the one with the squarish plug is the high level premium sound. I had the regular premium sound in my 90, and it had the two rectangle shaped connectors in it. The radio from that one, fits in my 92 and my dads 91. Both of those have the basic sound system.

[gadget73]

smallish square plug is the better premium sound. You can retain that amp and drive it with an adapter that connects to the RCA jacks on the new stereo. Or you can use the bypass harness and take it out of service. Two long rectangles could be either non-premium or the older style premium sound with the "football" amp and the goofy common ground stuff. The common ground you can't really do much with, and the only practical fix is wiring straight to the speakers.

[ojh]

smallish square plug is the better premium sound. You can retain that amp and drive it with an adapter that connects to the RCA jacks on the new stereo. Or you can use the bypass harness and take it out of service. Two long rectangles could be either non-premium or the older style premium sound with the "football" amp and the goofy common ground stuff. The common ground you can't really do much with, and the only practical fix is wiring straight to the speakers.

It has a commonground - the speakers wires were not paired at all. There were 2 rectangular connectors, one had what i think is speaker wires. The other had power wires etc. I paired the speakers wires as they came off the connector (i cut it loose) and nothing worked. I started removing wires and a couple speakers worked on what i took to be ground only - black w/white tracer. the grounds were run seperate from the other wires in the harness, they were added on in a group of three, the rest of the wires were cabled together in a twisted fashion an dthe colorcodes are different from schematics i found online. I downloaded 4 or 5 schematics including the connectors etc.
So i have to go to the trunk? I guess these wires go there and i can bypass the amp back there - i have cut off the factory connectors - so i can splice thru without running new wires? Daggone, best i invest in the factory manual.
Where abouts in the trunk is this amplifier? Are there 8 wires running from the factory radio to the trunk amp? So i can wire thru for the speakers without running new wires or will i have run wires for front speakers and repurpose 2 pair going back there?
What do you guys suggest? thanks, oj

[tjc78]

89 should not be common ground. It also should not have an amp with two rectangle plugs behind the radio

Its a shame you cut off the plugs. There are interface harnesses available at most auto parts stores or even Walmart so you don't have to cut everything and just match color for color with your new head unit

Like I mentioned before the amp is on the passenger side of the trunk bolted to the back of the rear seat. (In other words to the right of the spare tire). I doubt you will see one since you don't have the square plug behind the radio. The football shaped, common ground amp went away in 1987IIRC.

[jaywish]

I thought 89 was common ground. Could be wrong though as it has been a while since I looked. Though maybe that is only the premium sound and basic sound. There was a higher level available.

Best idea you had was the factory service and electrical manuals. It will help with the whole car.

Was the radio oem? Post pics front & back.

[tjc78]

I know the square plug premium sound isn't common ground. I thought 87 was the last year of common ground, but according to the OP I may be wrong.

[HiFiMerc]

My 90 was a common ground. Ran all new wiring when an aftermarket head unit was installed.

[ojh]

I did this last Saturday and the radio/connectors are long gone. I also replaced the valve cover gaskets, between them and the factory wireing i can claim temporary poor judgement when i actuelly cleaned up and threw out the trash. it won't happen again.
I want to thank you guys for the terrific help. I'll be able to work on the car tomorrow and have a looksee into the trunk and we'll go from there. I checked ebay and there are some good authentic looking electrical manuals - are there any i should avoid?
thanks again, oj

[gadget73]

Its partially common ground. The feed to the amp uses 3 wires per channel, a left +, right + and - for both the front and rear, for a total of 6 wires. The output side of the amp has the normal 8 wires, 2 per speaker. Theres no practical way to bridge these, so you're sort of left with running new wires to the speakers.

[HiFiMerc]

Interesting. Another cost saving measure maybe. You get rid of those two extra wires in every car that comes with premium sound, and it adds up.

[ojh]

Its partially common ground. The feed to the amp uses 3 wires per channel, a left +, right + and - for both the front and rear, for a total of 6 wires. The output side of the amp has the normal 8 wires, 2 per speaker. Theres no practical way to bridge these, so you're sort of left with running new wires to the speakers.

That explains a lot, i could read more than a single speaker on each ground and could not identify left or right. At least one of them had a direct short to ground because the original radio didn't work right when i bought the car. The only speaker i have replaced so far is in the drivers' door. I have the car in the shop now and will get into it later, i plan to locate the remote amp (assuming it has one) and ring out at least 2 pair of wires to connect for the rear speakers and i'll have to dig into the front harness' for the door speakers and extend them to the new CD player.
All's good, I have a game plan!