battery light comes on at idle
- Thread starter BJBethel
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Glaze
New Member
That's normal. I had an idle hiccup some time back on the '94. When volts get down to about 10V and there's any sort of load on the E-system, the amp light begins to flicker or come on faintly but constantly.
You might also notice your radio turns off, along with the dash clock and something else (I cant remember what else right now).
If your idle is low, or it gets low during the low-volts situations, I'd raise the idle up a bit and see how it does. For me, it was a low idle causing the low alt output, ergo the voltage drop, ergo the clock turning off.
Random thoughts.
Good luck.
You might also notice your radio turns off, along with the dash clock and something else (I cant remember what else right now).
If your idle is low, or it gets low during the low-volts situations, I'd raise the idle up a bit and see how it does. For me, it was a low idle causing the low alt output, ergo the voltage drop, ergo the clock turning off.
Random thoughts.
Good luck.
Glaze
New Member
one suggestion might be to go to local generator/alt place and see if they have a smaller diameter pulley for the alt which i believe will increase revolution. I did this on my 91 but im not sure if a smaller pulley is available for the SN95 alt 3G?
glowstang93
Dirt-Old 20+Year Member
4 years ago when my alternator went out, I put in a new one from Advance and as soon as I put it in, the battery light came on dim. It tested good, but my mechanic said there was a bad diode inside the alternator. Took it back and tried another one, no problem. Could be a bad diode in the alternator. Is it the stock unit or a 3g? The stock had such small diodes so close to heat they were crap.
Glaze
New Member
id have the alt bench tested....any good reputable generator shop should tell you if its going bad or not
Black1987Stang
Active Member
my battery light came on about 2 years ago, charging voltage was real low, swapped in a new autozone alternator good to go
If raising the idle just a hair (toeing the gas pedal) makes the light go off, I'd recheck the idle. The 94-95 cam idles really smooth - I've run my idle down well below the commanded value (to about 500 RPM) and it was smooth as can be.
In my case, I didnt perceive an issue with the idle being lower (the stock tach is too inaccurate and the car idles smooth anyhow), so it was using a diagnostic tach and simply raising the idle a little bit that helped me. Plain and simple. Not that any of that applies to you - it's just what I figured out and how I fixed it on mine, in case it helps a little.
Other things to check: Peel back the regulator wiring loom at the alternator. The heat under the low SN hood vulcanizes the insulation bad (I had bare regulator wires sitting next to eachother inside the loom. The insulation had baked and fallen off). Those wires are voltage sensitive, so having them clean and completely functional is imperative.
Do take a look at the stock charge cable - it's kind of a POS. I chose to replace mine with new 4 AWG cable (that stocker looked like it was maybe 6 AWG. Mine was droppin 400 mV, which is not acceptable personally). This will likely not be related to your issue but is just good to do.
And check the power distribution box connection (where your charge cable connects to the underhood fusebox, along with the positive battery cable). That connection can be troublesome on 94-95's.
I'd really double check that idle and note if adding 100 RPM or so with your foot on the gas helps. If so, a gas reformulation (winter blend) or some sensory input for colder weather is likely afoot.
Random thoughts. Good luck.
In my case, I didnt perceive an issue with the idle being lower (the stock tach is too inaccurate and the car idles smooth anyhow), so it was using a diagnostic tach and simply raising the idle a little bit that helped me. Plain and simple. Not that any of that applies to you - it's just what I figured out and how I fixed it on mine, in case it helps a little.
Other things to check: Peel back the regulator wiring loom at the alternator. The heat under the low SN hood vulcanizes the insulation bad (I had bare regulator wires sitting next to eachother inside the loom. The insulation had baked and fallen off). Those wires are voltage sensitive, so having them clean and completely functional is imperative.
Do take a look at the stock charge cable - it's kind of a POS. I chose to replace mine with new 4 AWG cable (that stocker looked like it was maybe 6 AWG. Mine was droppin 400 mV, which is not acceptable personally). This will likely not be related to your issue but is just good to do.
And check the power distribution box connection (where your charge cable connects to the underhood fusebox, along with the positive battery cable). That connection can be troublesome on 94-95's.
I'd really double check that idle and note if adding 100 RPM or so with your foot on the gas helps. If so, a gas reformulation (winter blend) or some sensory input for colder weather is likely afoot.
Random thoughts. Good luck.
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