Electrical issue on my F250

[OldRedFord]

On my 1997 F250, I had gone on a 200 mile round trip in my truck yesterday.

Was headed back to the house and started to notice every time I came to a stop I could hear this intermittent whirring sound. Didnt think much of it, had just pulled a horse trailer 200 miles. A little bit farther down the road I came to a stop and then I noticed the warning light for the charging system pulsing in time to the whirring sound.

Pulled over and opend the hood. Jiggled the wires on the alternator, light still pulsing. Revved engine and the light stopped pulsing. I noticed the lug on the back of the alternator that has the red plastic between the charge and the alternator body was melted. Shut the hood, revved the engine again and continued on my way. Stopped at another traffic light and this time the whirring sound and the pulsing light dissipated and hasn't come back.

Bad alternator? Or a bigger problem?

[BRUTUS_T_HOG]

more likely a bad connection between the alternator and the battery or the ground cable to the battery

[OldRedFord]

Well today it did it again. This time for whatever reason when the alternator warning light was flashing I started to mess with the settings for the climate control. I made note that with the AC on the light went out, with it off the light would flash. I will also add that twice now the blower has stopped working all together. Also after shutting down the truck and letting it sit for a few minutes everything would be normal again.

Its still a intermittent problem.


Between the alternator and the battery with the engine on I am getting 16 volts.

All battery connections are tight, same with the alternator.

[basketcase0302]

Between the alternator and the battery with the engine on I am getting 16 volts.

Tim, I would double check that voltage. If your reading is right it sounds like your voltage regulator is shot. Charging should be max around the upper 14 volt range if I'm not mistaken. Pull it into an autozune or discunt auto they will test the charging system for free on it.

[OldRedFord]

Im pretty certain I am getting 16 volts from the alternator.

[basketcase0302]

OldRedFord on Mon Aug 08, 2011 9:35 pm
Im pretty certain I am getting 16 volts from the alternator.

At the alternator would be fine-if I'm not mistaken, that's too high at the battery positive.
Maybe TF or someone else can pipe in here as well.

[BRUTUS_T_HOG]

test with a real voltmeter. 13.5V-14.5V is correct. 16V will cook the battery to death. before replacing the voltage regulator make sure all the wire connections on the alternator and between the regulator are clean and in good condition.

if the regulator sees low battery voltage due to bad connection of course its going to overcharge thinking its making things right.

also don't trust the mouth breathers at any chain parts store. goto an electrical place where they know what they are doing. chain store "techs" usually go by the tester saying good or bad

[OldRedFord]

test with a real voltmeter. 13.5V-14.5V is correct. 16V will cook the battery to death. before replacing the voltage regulator make sure all the wire connections on the alternator and between the regulator are clean and in good condition.

if the regulator sees low battery voltage due to bad connection of course its going to overcharge thinking its making things right.

also don't trust the mouth breathers at any chain parts store. goto an electrical place where they know what they are doing. chain store "techs" usually go by the tester saying good or bad

Does a digital Fluke brand multimeter work?


Electrical place? All I have around here are Nappa, O'reillys, AutoZone and Advance.

[BRUTUS_T_HOG]

a fluke is great. i just wanted to be sure you don't go off the gauge.

parts people usually don't know whats going on in the charging system aside from what they're "go" - "no go" machine tells them.

meaning they will tell you you're alternator or regulator is bad when it could actually be corroded wiring or bad connection because they don't always know better than the machine tells them

[cdeal28078]

Yeah a Fluke is top brand stuff. Wish I still had one.
clint

[BRUTUS_T_HOG]

Yeah a Fluke is top brand stuff. Wish I still had one.
clint

i have a fluke 233, best tool i've bought so far! has all the features of the 88, but has a wireless display and costs half as much

[basketcase0302]

Tim,

Like said above, that Fluke is the top dog as far as meters go.
Test it on the battery by itself and see what it reads / then fire up the engine to make sure the meter reads a difference. Doubtful the meter is wrong. I'd say your voltage regulator is shot.