Here's the deal. I know my carb is bad, but choke light come on but doesn't stay on. It comes on when I brake, and sometimes it blinks along with my turn signals when they are on. I'll be replacing my CARB soon, but what I really need to find out is whether I need to check my electrical system as well.

Thanks

Jeff Morgan
82 firebird S/E
original 305
original exhaust

 

By a feat of amazing engineering ingenuity, some engineer decided to make that one light serve 2 functions.... it's also the "Alternator" light! Hmmm, let's see, I've got a Choke in one hand, and an Alternator in the other.... by golly, these 2 things are almost exactly the same! Look at this, they're even both made out of metal and plastic!! And they both go under the hood!! This is incredible!!!!!! Why don't we just label the Alternator light "Choke", surely every auto user in the country no matter how little they know about their car's inner workings will immediately understand what it means!!! Great idea!

Sounds ridiculous? but it's true. You need an alternator: that's what "Choke" means. It just so happens that the electric choke heater supply is tied into the alternator circuit in such a way that the choke won't get power unless tha alternator is charging, i.e. the engine is running; that way the choke will stay on the right length of time even if you turn the key on and leave it on before you start the car.

Whatever. Get an alternator.

 

That explains why my choke light came on when I drove my car after letting it sit for 4 months. Funny thing is, I also heard a faint buzzing sound. Is there a buzzer in there somewhere, like the one that sounds when you leave the keys in the ignition and open the door?

 

There's a relay in the "convenience center" under the dash, that is energized by the alternator's output, that feeds power to the choke. As it happens, that's where the key buzzer is too. When an alternator has the problem that yours does (bad diode trio) it outs out power in bursts, rather than a continuous stream, and the relay drops put and pulls back in many times a second because of it, especially at idle. It usually quits when the motor speeds up. And higher speed makes the light dimmer too.

 

So many mustangs so little time;

Thanks for your input. So, why does my engine (sometimes) stay choked up for 20 t0 30 miles after start-up. It will not kick down. Sometimes it will, and sometimes it want. Does that have anything to do with what's going on with the alternator? Funny thing, I haven't had any problems with my alternator, but like you said, it's going bad. So, what does the alternator light mean on my 82 bird, if the choke light means "alternator"?

Thanks for your help

Jeff Morgan