smp5937

At night, when I am using my lights, and turn on my wipers (or NOT) and turn on the blower motor to defrost the windshield, the volt gauge goew waaaay down to about 8 VOlts...If I turn off the blower it charges up quickly back to about 14 volts...anyone else have this problem? And know what to do about it? I am thinking the motor may be failinf and drawing a LOT of current...

The truck is a 1988 F150, auto, 4x4, 5.8L...

Carbuff

On my 94 I get the same thing at idle. But once I get the motor rpms up there a bit it goes back. Ive seen this on lots of cars. Its possible that you have a smaller battery than what is specified or someone changed out the alternator with one of lesser amperage. As long as it stays in the zone on the gauge you should be ok.

smp5937

Mine does not go back up no matter what the RPM's, just if I turn off the motor...I have not experimented to see if the headlights are dimming or if wipers are slowing down...but I will...I just got this truck a couple weeks ago and haven't driven it much yet...

tonkatruck66

my '91 goes below the gauge. i dont really worry about it. sometimes if the rpms get low enough it actually dies and comes back, but thats only happenned once.

smp5937

Hmmm, sounds like I shouldn't worry...I think I will get it all going and verify what teh alternator is putting out and what is in the battery while it is all running...thanks for all the input!!! I appreciate that!!!

smp5937

OK, found out what the problem was, and got it repaired.

Yesterday I was outside changing the wheels and tires out on my truck, and after running it for a while I went then and parked it.

Went out later and tried to start it but the battery was dead. I checked voltage and it had about 6.5 volts...

Put the charger on it and brought it up to par, then started it, and checked the battery again, and VOILA"!!! It showed 12.2 volts!!!! Wel, it SHOULD have shown 14.x volts, but the alternator was not charging the battery...

Took it to a shop today and it was only putting out 6 amps...

Bought a new one, installed it, started the truck, checked voltage at the battery....14.x volts!!!! Yessssss!!!!!

Turned on all accessories and checked the voltmeter, it did not draw down hardly any...

Problem solved.

flip47553

I just upgraded my alternator to the 130 Amp Mustang. Much Brighter and Better Lights. Pretty Much 14.4 at idle. Big difference. No more 70 amp.
It bolted right into the factory bracket. Visit this site for info: http://www.fordfuelinjection.com/?p=75