My alt warning light doesn't come on when turning the key. What's up

[chrisp]

The alternator warning should come on (along with the oil pres warning light) whenever the ignition switch is turned to the on position when starting the car. Mine no longer does.

Any ideas on the problem? I haven't checked the volts to the battery but I suspect my alternator is fine as it was just replaced 4 months ago. I'll check that tonight. All fuses in the front luggage compart look good. Could it be a fuse somewhere else (everything else electrical works fine)?

[Jdub]

This is often discussed here; the Search mechanism can help in these situations.

For a nice writeup, see http://www.pelicanparts.com/cgi-bin/vb/showthread.php?s=&threadid=51717

Jw

[john walker's workshop]

that's the exciter current that gets the alternator into the charging mode. if the brushes are worn down, the circuit can't ground and the light won't come on. possibly it's the bulb. put a voltmeter across the battery terms. when you start the engine, the voltage should increase. 13.8-14.2 is normal.

[chrisp]

I put a test light accross the connections to the back of the alt warning light. The test light doesn't light either....so it's not the battery.

I'll check the current as planned but if the current is okay then I have no idea what's up. That's why I am fearing. Without this warning light I am running a little blind and I am ignoring some other (potentially) bad condition.

[chrisp]

SOrry, I meant to say "bulb" in the first sentence...not "battery" Sorry.

[john walker's workshop]

the black/red wire is just "key on" power that also powers other bulbs, etc. your test light should work on that. the blue wire goes to the alt and regulator (if it's external), and grounds thru the alt circuit. it passes thru the 14 pin connector in the engine area, so check that for corrosion.

[joehahn]

...how about on a 1968 car John? Is it similar? Is the test similar?

[john walker's workshop]

same, except there's no 14 pin connector.