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Posted by: p914 Nov 6 2004, 08:00 PM

I just had my alternator go out . In addition my dash light didn't work and it is part of the circuit for the charging system to work..

Anybody else heard of this?

Posted by: Carlitos Way Nov 6 2004, 08:03 PM

We had a similar situation with my parents Tempo (their choice, not mine), about 10 years ago. 3 different dealerships looked at it, and it wasn't until we escalated it to Ford's customer service that they finally found the problem... 3 alternators later, within 2 years.

Posted by: vsg914 Nov 6 2004, 08:07 PM

yep, light no work, no charge.

Posted by: SirAndy Nov 6 2004, 08:18 PM

Posted by: Joe Ricard Nov 6 2004, 08:24 PM

Technically the light is required to supply the excitation voltage to the Alt. field winding. You could do it with a resistor but that would be dumb. my 928 had a resistor in parallel to the bulb incase the bulb burned out.

Posted by: p914 Nov 6 2004, 11:25 PM

That's what my mechanic said too. He explained the entire process. Funy that a dash light would serve dual function.

Posted by: jim_hoyland May 21 2016, 08:09 PM

Rich at WCR: several thread address this. Hope it helps...


Attached image(s)

Posted by: timothy_nd28 May 21 2016, 08:19 PM

Replace that light with an LED, and the alternator will quit working too

Posted by: ssuperflyoldguy May 21 2016, 09:56 PM

Had an open amp gauge that caused mechanic to change alternator, jumped around it & started charging

Posted by: r_towle May 21 2016, 10:12 PM

Yes

Posted by: RobW May 22 2016, 08:13 AM

How can you test the connection to the alt gen light? If the light is on and stays on, then its the generator right?

Posted by: jim_hoyland May 22 2016, 08:21 AM

Right. When the ignition is turned to on and the light doesn't come on was the problem. The test for this is whether the alt light is getting 12v or not; if there is power and no light then the bulb must be replaced.

Posted by: RobW May 22 2016, 08:28 AM

Thanks. I guess I still need to change my alternator.

Posted by: brant May 22 2016, 09:13 AM

Posted by: jim_hoyland May 22 2016, 10:09 AM

Question: Is the alt light bulb the same as the oil light bulb ?

Posted by: Dave_Darling May 22 2016, 11:34 AM

Same kind and voltage.

BTW, if the voltage regulator is not plugged in, you won't get an alternator light and the alternator won't charge. Don't ask how I know that...

--DD

Posted by: jim_hoyland May 22 2016, 12:37 PM

Will the alternator light work if the VR is bad ?

Posted by: Dave_Darling May 22 2016, 09:29 PM

Depends on what has gone bad in it.

--DD

Posted by: mbseto May 23 2016, 11:31 AM

[mal]function, seems like... so is there also a fuse in the circuit?

Posted by: worn May 23 2016, 11:38 AM

Yep. Also you need a two watt bulb or more to get the alternator stated. If you look at the wiring diagram it is one of those clever engineering feats in which the gen light is initially used to bootstrap the windings on the alternator. The way they set it up it warns you of more than one problem using no electronics - just a 2 watt bulb!

Posted by: rhodyguy May 25 2016, 10:57 AM

Yes. Generally 'does the red light illuminate when the key is turned to the first position?' Is the first ? asked with charging issues. Generally......but not always.

Posted by: 7TPorsh Sep 19 2016, 08:29 PM

Bumping an older thread here....

If there in alt light (missing) will alt charge? I see a bare blue wire behind the gauge....must have disconnected from whatever it was connected to.

WHat can I tie it to if there is no light?

Car was charging and now not....

Posted by: timothy_nd28 Sep 19 2016, 09:02 PM

I'm confused Why not just reattach the wire? The alternator needs the lamp or resistor, something for it to start charging.

Posted by: 7TPorsh Sep 19 2016, 09:27 PM

Here's the mess I'm looking at....turns out the loose blue wire was just extra.....in the pic is the alt light in the wrong socket? Look like i'm short somewhere....the ebrake light works.

Posted by: 7TPorsh Sep 19 2016, 09:33 PM

Also interestingly, the alternator hums now when I didnt notice it before....is that normal? Hum stops when I unplug the VR. Is alt going bad?

Posted by: timothy_nd28 Sep 19 2016, 09:40 PM

Two bulbs in the wrong socket locations

Posted by: 7TPorsh Sep 19 2016, 09:54 PM

This helps....there should be another bulb next to#3 on combo gauge ?? the open hole

Looks like this now

Posted by: timothy_nd28 Sep 20 2016, 06:54 AM

Closer, but you still have the oil lamp and gen lamp switched.