View Full Version : Alternator problem - 1990 Celica GT

05-15-2014, 06:24 AM
Hi, I was wondering what the specs are for the battery warning light diode in a 1990 Toyota Celica GT, as described in: EDIT: I HAVEN'T BEEN A MEMBER LONG ENOUGH TO POST LINKS


I seem to have the same problem, and don't know what kind of replacement I should order (probably from Digi-key, as replacement OEM parts seem impossible to find). Or if you know somewhere I can order an actual replacement? For that matter, I don't know for sure where to even find that diode, as I've taken apart my interior except for the instrument panel, since I drive it to work daily...

Measured the output of all 3 pins connecting to the voltage regulator on the alternator, all measure 12.xx volts. This points to a fried battery warning light diode, as that website indicated.

The battery discharge light NEVER comes on, not even with the engine off and ignition on.

The alternator puts out no power under any circumstances.

For the last couple months it was charging irregularly, and the battery warning light was always on. The battery voltage would be swinging from 10V all the way up to 18V, so I replaced the voltage regulator. Shortly after doing so, I shorted the alternator while checking bolt tightness before I started the car, but nothing seemed wrong and the battery warning light wasn't on, so I assumed it was fine. However, the alternator no longer works at all.

The main ALT 100A fuse is fine, as in the 40A AM1 fuse, and the 7.5A IGN fuse.

If anyone could tell me anything about this problem I'd be very grateful!