Mechanics

ALTERNATOR NOT CHARGING, BATTERY LIGHT ST

1988 Toyota Supra

Electrical problem
1988 Toyota Supra 6 cyl Two Wheel Drive Manual 180000 miles

Hi, I have an 88 Supra NA which I have replaced the alternator on 2 times. 1 Alternator had tested good from Autozone, tested bad when returned. I have checked wiring, fuses and fusible link and no discernible problems. Originally when I got car someone had run a wire across a damaged fusible link (could it have damaged something else along the way?). I replaced it with a 100A link. When I start the car, the battery light stays on. If I run the car at 4000rpm or more and keep it there, light goes out. Is the fusible link the correct value? I cannot find any reference to the NA model, just the Turbo, which is 100A.

Any help is greatly appreciated.
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Lcp2000
January 18, 2010.



If the wire fried the fusible link, there may be other damage to it. Use a Meter to measure the resistance (Ohms) of the main charge wire to the + battery terminal.

Tiny
Jack42
Jan 18, 2010.
I've traced all wiring inside the engine bay and everything seems ok at first glance. There are three wires that come out the plug in back of the alternator and one thick one that bolts on top. I'm assuming the thick one is the charge wire? Should I be measuring this while everything is connected to BAT and ALT or just wires alone?

Thanks.

Tiny
Lcp2000
Jan 18, 2010.
Just the wires. Should be little to no resistance in the charge wire (big one)

Tiny
Jack42
Jan 19, 2010.