Hello Scotty, a former website helper here, the alternator finally died on my 1999 celica. Got a new remanufactured alternator. When I went to unplug the old one the connector just fell apart in my hand. The 3 connectors pulled out before I thought about which one goes where. (note- The label on the alternator is completely faded). The wires are so old they have changed color but I used isopropyl alcohol to clean them off and I have a red/black wire, a darker beige and a lighter beige wire. I tried lightly scraping the outside to see if I could get more color but to no avail. From the top down, from top to bottom (closest to the firewall to closest to the front of the car), is the wiring, in order lighter (white?), red, darker (yellow?). Any advice appreciated.
Don't worry about the wire colors.
You have 3 wires that go to the alternator terminals labeled "L", "IG", and "S".
You can use a test light (or a multimeter, but it's best to use a test light) to determine which of those wires from that broken connector goes where.
Here's how it's wired:
If you turn the ignition on you'll measure 12 volts (+ or -) on all 3 wires with a multimeter so don't do that.
With Ignition off, find the wire that has battery voltage (12 volts + or -) That wire goes to the "S" terminal on the alternator.
Here's why using a test light instead of a multimeter is a good idea for the other 2 wires.
If you refer to the wiring diagram above, the wire going to the "L" terminal on the alternator goes through the "Charging Warning Light. on the dashboard.
And Ohm's Law says that when you use a test light on that wire (wired in series through that bulb to the "L" connector on the alternator), it has to share the voltage and will light the test light dimmer than the wire going to the "IG" terminal.
So ENGINE RUNNING, one of those other two wires will light your test light brightly. That's the wire that goes to the "IG" terminal on the alternator.
The one that lights the test light dimly goes to the "L" terminal on the alternator.
Or if you're using a multimeter and not a test light, here's how:
With the ignition ON, when you remove the 10A Gauge Fuse and you lose power on one of the other two wires, that's the wire that goes to the "IG" terminal on the alternator.
And when you remove the 7.5A IGN Fuse and you lose power on one of those other 2 wires, that's the wire that goes to the "L" terminal on the alternator.
Now to the alternator connector. Here's how Toyota wires them:
Hope that's helpful.
Great answer @jack62.
Wow, what a great answer. Thanks. I went to the junkyard to look but no Celicas of my vintage (1994-1999) at all and the Camry's of the same vintage, and even Corollas I happened upon have the obviously yellow, red and white wires so that wasn't helpful. I need to get a test light and then I will follow your procedure. I am humbled by your detailed response.
I got it all wired up and it worked like a charm thanks to you jack62! Thanks again.
You're welcome and thanks for coming back and letting us know that everything worked out OK
I would buy a new connector and splice it in
Yes. Done. There is no connector available from Toyota. So, aftermarket is only option, and then, which pin goes where? The connector has red, black and yellow wires. Which of my wires goes to which of those.
did you try web searching for a schematic, or asking in a Celica forum?