Okay, on my car the other day the choke light would not go off on the dash, and we could not figure out what was wrong, so we disconnected it at Krispy Kreme donuts (now on the berlin turnpike, waited 20 minutes for a damn donut) and drove it home. Noticed the voltage gauge was low, so we checked it, and the alternator was bad. No red light for the battery, thank goodness for real gausges. Why would the alternator being bad trigger the light. The alternator was replaced, the light went on for like 2 seconds and then went off for good. Should I just assume it was the alternator? What does the alternator have to do with the choke. I know its electric, but wouldnt it draw power off the battery vs. the alternator?

 

It was the alternator.

For some reason, they made it so the choke light comes on until voltage exceeds a certain threshold. I forget what that number is, but that's why it came on when the alternator was bad.

 

Thank goodness, I was worried my carb was messed up or something. It went right away though when the alternator was swapped. Of course a battery light wouldve been more obvious than the choke light in tipping off a bad alternator

 

It's actually even simpler than that...

The Choke relay and the Choke light are in series between battery and ground with their common point hooked to the idiot light terminal of the alternator, such that if the alternator is charging, it will generate 12V there, which will put 12V on both sides of the light (turning it off) and energizing the relay. If the alt is not working, the light will be on by way of current able to flow from the batt through the bulb into that terminal of the alt, and the relay will not be operated since it will have ground on both sides of it, so the choke heater will not be receiving power. I suppose that last little tidbit is why they labelled the light "Choke".

So, bottom line is, the "Choke" light is really the "Alternator" light, it's just mis-labelled. I won't even guess what stupidity caused the factory to do such an idiotic thing, so that the light fails to communicate to any but the most technical car owner what the problem it's complaining about really is; but I can only assume that they had a reason why they chose that label instead of the one that actually provides useful information.

 

:hail:

 

RB,

The light actually comes on when the choke heater relay goes nutso and starts chattering.

It doesn't come on if you forget to connect the choke wire, though...

 

Some one of these days I'll get off my dead lazy butt and scan the schematic... it makes it pretty clear what's going on... the buzzing relay and the dim light are more symptoms of electrical problems that have nothing to do with the choke, except that the choke doesn't get its power. You're exactly right about the wire though, any kind of actual "Choke" failure won't light the "Choke" light. Now that makes alot of sense, doesn't it!!

 

I want to make sure I have it right. Disregarding the alternator thing, the choke light should come on what the choke is on??

 

It comes on when the key is on, but the alternator is not charging. Under those same circumstances, no 12V will be supplied to the choke heater, so if the engine is cold enough that the choke is on, it will stay on. Once the alternator begins charging, the power it produces both extinguishes the light and operates the realy, which then supplies power to the choke heater.

 

I think you told me that once before RB. I'll get it sooner or later!