I was taking my fiero for a spin earlier today and the battery meter was only reading 13 volts which I thought was weird it seems a tad low and when it got darker I went to turn on my headlights and they only went up about halfway I had to hold the switch half on half off for them to go up fully would this be a weak alternator?

quote Originally posted by Josh86gt: ...would this be a weak alternator?

Probably. Should be showing a charge of more like 14.6v

quote Originally posted by Patrick: Probably. Should be showing a charge of more like 14.6v

Okay thanks it's been worrying me for a while some of the lights on my dash also flicker but that could just be a loose connection

Before changing the alternator... make sure the connections (on battery, power junction, and ground) are corrosion-free and tight. Use a standalone volt/multimeter to measure what the alternator is putting out.

[This message has been edited by Patrick (edited 03-16-2025).]

Start with a fully charged battery as the Generator/Alternator will not even try to charge an undercharged battery...

Use a voltmeter to measure the battery - 12.5 DC Volts or Better
*If the battery won't hold 12.5V after charging - replace it

Check the Generator/Alternator Belt Tension

With a fully charged battery...
Use a voltmeter to measure the battery at idle AND 3k RPM - 13.5 volts to 14.5 volts
*If the Generator/Alternator won't charge the battery at 13.5 volts to 14.5 volts...then

Check the Generator/Alternator Connections
With the KEY at RUN position {Engine NOT Running}
Check All Cable/Wires Have 12V
*If NO, check the fuses/wires/cable
*If ALL have 12V - replace the Generator/Alternator

------------------
Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles

[This message has been edited by Vintage-Nut (edited 03-17-2025).]

Okay so I finally got around to testing my alternator and it worked just fine but my headlights still seem to not go up when I flip the switch all the way I have to hold it halfway and some of the lights on my dash tend to flicker when I turn them on would that be a bad headlight switch?

quote bad headlight switch?

Start there, you can try cleaning it or:

The Fiero Store Headlight Switch / Part # 51426
https://www.fierostore.com/.../Detail.aspx?s=51426

AC Delco
https://www.partsgeek.com/v...eadlight-switch.html

Wells
https://www.partsgeek.com/f...eadlight-switch.html

Standard Motor Products
https://www.partsgeek.com/4...eadlight-switch.html

Edit for a Warning
The headlight switch is HOT at All Times!
Disconnect the battery before removing the switch

[This message has been edited by Vintage-Nut (edited 03-18-2025).]

Okay so I finally got around to taking out the light switch does anyone know how to disassemble it without breaking it?

If it is sealed - 'flood' the unit with electrical contact cleaner as flipping the switches

Fully Dry It, and Test It...

quote Originally posted by Vintage-Nut: If it is sealed - 'flood' the unit with electrical contact cleaner as flipping the switches Fully Dry It, and Test It...

Ok thanks

quote Originally posted by Josh86gt: Okay so I finally got around to taking out the light switch does anyone know how to disassemble it without breaking it?

i usually just grab the ones from a firebird or camaro imma be real. i think theres some plastic tabs somewhere

a new switch is surprisingly cheap.

quote Originally posted by richard in nc: a new switch is surprisingly cheap.

$20 on rock auto

Apparently, this is another thread which the OP didn't respond as it is 'solved' or not...

quote Originally posted by Vintage-Nut: Apparently, this is another thread which the OP didn't respond as it is 'solved' or not...

I have not solved it yet I replaced the switch and it is still broken and I'm just going to leave it alone for now