Battery light

[Anathollo]

Well I pulled into campus and rolled down my window to pay for parking and noticed my truck sounded like shit. Then the battery light came on. I parked, hopped out and pulled out my voltage tester and it coincided with my volt meter that I have in the truck. I'm holding at 12.5V instead of the usual 13.5V.

Now my question is: how do you check the output of the alternator? In this case I'm not sure its a bad battery. I just replaced it with a Diehard gold series (yes I know Sean....).

And Im in pay by the hour parking too

[taco4x4rar]

Does your truck start? Dealt with a similar problem on a landrover once thing would stumble and fall on its face when you tried to rev the engine replaced the alt and it fixed the problem

[TacoXpo]

While truck is running you will probably see about 15v if your alt is working.

[BearsFan07]

While truck is running you will probably see about 15v if your alt is working.

15v? With my scangauge I only see about 13.7v. In the old days I used to see volt meters hit 14.4v at higher RPM's but I haven't seen that so much with my Taco.

[BearsFan07]

I just replaced it with a Diehard gold series (yes I know Sean....).

Uh huh... well at least it wasn't an Optima.

[BearsFan07]

Oh, but back to your question. Go pull into an VatoZone or similar store.. they should be able to test the battery. As for the alternator they'll probably make you pull it off the truck. If its putting out 12.5 volts at idle thats not that bad... might be normal operating voltage at idle.

[Anathollo]

15v? With my scangauge I only see about 13.7v. In the old days I used to see volt meters hit 14.4v at higher RPM's but I haven't seen that so much with my Taco.

X2

[Anathollo]

Oh, but back to your question. Go pull into an VatoZone or similar store.. they should be able to test the battery. As for the alternator they'll probably make you pull it off the truck. If its putting out 12.5 volts at idle thats not that bad... might be normal operating voltage at idle.

Yeah I'm going to check it out when I get out of class. I'll have to play around with it. My truck sounds like shit. Almost like a pulley has worn out. It's got a high screech sound coming from under the hood.

[AlienXtx]

Go from ground to the hot output on the Alt, it should read 13.5-14.5 at idle.

[BearsFan07]

Well that maybe the issue then all together.. slipping belt causing the alternator to not spin... or worse case.. seized bearing in the alternator.

[AlienXtx]

Well that maybe the issue then all together.. slipping belt causing the alternator to not spin... or worse case.. seized bearing in the alternator.

This ^

[TacoXpo]

15v? With my scangauge I only see about 13.7v. In the old days I used to see volt meters hit 14.4v at higher RPM's but I haven't seen that so much with my Taco.

You're right - I'm off. 13.7 sounds about right! My foggy brain was confusing 13.5 with 15!!!!

[BearsFan07]

Maybe yours did hit 15v. just needed a new voltage regulator.

[TacoXpo]

[Anathollo]

Well that maybe the issue then all together.. slipping belt causing the alternator to not spin... or worse case.. seized bearing in the alternator.

Ok, so I need to look at getting a new belt? I was gonna change it out at a 100k miles anyway. I guess while I have it off, the I can turn the pulley on the alternator and see if its seizing up.

[BearsFan07]

Ok, so I need to look at getting a new belt? I was gonna change it out at a 100k miles anyway. I guess while I have it off, the I can turn the pulley on the alternator and see if its seizing up.

Yeah, I'd start there. Belt should be pretty cheap.. I think I paid about $30 for the spare I carry (genuine Toyota part that I picked up online) Worse case you spend money on a belt and now you have a spare. Could be a tensioner as well. But I'd start with the belt and have the battery tested while you are getting the belt.

[Anathollo]

Yeah, I'd start there. Belt should be pretty cheap.. I think I paid about $30 for the spare I carry (genuine Toyota part that I picked up online) Worse case you spend money on a belt and now you have a spare. Could be a tensioner as well. But I'd start with the belt and have the battery tested while you are getting the belt.

Will do!

Thanks guys

[SecretSquirrel]

I'm going with the bottom-most (#1) pulley.

[drew02a]

I wouldn't rule out the battery, this heat is hell on them

Super easy to have tested too

[yotarob]

. You dont see to many of the Denso alts going out very often unless they have gotten wet. You should be seeing more voltage with it running though. If it is squealing then it could be the pulley or a bad tensioner / loose belt.