weird 1985 corolla stereo

okay.  I can't be the only person in the world with this problem, but I have had a hard time finding out the solution....

My '85 corolla does not have the wiring harness described in the wiring section, in fact, it has only 9 wires coming into the back of it.  I have worked out that there are four negative speaker wires and one speaker ground (they all ground together).  The other four wires should be: ground, constant power, switched power, and illumination/dimmer (my stock deck dims with the dash lights, is that normal for an '85?).

now, I don't know whether it is because I am from australia or what, but my radio seems to be different from everyone elses.  The colours on the radio harness don't match at all with the cars end, and neither match with what is said on this site.  following is a diagram of the harness, and the known/suspected wires:

| (1) | (2) | |       | | (3) | (4) |

| (5) | (6) | | (7) | | (8) | (9) |

1: right fron -ve      2: left fron -ve      3: Illumination????      4: switched power????      5: main power????     6: all spkr +ve (gnd)       7: main ground???? 8: left rear -ve      9: right rear -ve

If anyone out there has solved this puzzle, could they please enlighten me, I am very cautious about ruining my beautiful new HU.

Cheers

I would recommend you find yourself a DMM (digital multimeter) and test out those other wires yourself.  No matter what we tell you you're still gonna have to verify it first anyways... The constant should show approx. 12 volts all the time, and the switched 12 volts should show approx. 12 volts only when the key is in the accessory or on position--the voltage should go away as soon as the key is turned to the off position and removed from the ignition.

As for the illumination wires, I'd stay away from those as many times it's kinda tricky to figure out which one is which and unless you really really want the dimmer/illum. feature of your new head unit, it's just not worth the risk.  Not to mention many aftermarket head units don't even have wires to hook up to dimmer or illumination wires.  Just tape them off and leave them be.

Now as far as the common ground speakers are concerned, you can get an adapter from either Peripheral or David Navone that will convert the floating ground output of your new head unit to the common ground speaker wiring of your car.  Ideally to get the best sound you're gonna want to get some aftermarket speakers at some point, but this will require running new speaker wires.  However if you did it all at the same time you wouldn't need to buy those adapters cuz you'd just be using your new wiring.  Just something to think about....