Alt Question HELP!!!!!!!

[ABoyAndHisToys]

I have dual alts in my truck and I believe the bottom is shot. My battery light is on but my volts are staying up on my gauge. When my primary alt went out a few months ago the volts dropped quickly. My question is, if my lower is shot will my primary keep the truck from running on batteries. I'm at work till 4am and want to make sure I can make the 80mile trek home.

[bigcountrysg]

Yes if your secondary is failing. Your primary will power the truck.

[ABoyAndHisToys]

Wooooooo!!!!!!! Thanks for the input. I'm gonna scan it when I have a chance just to make sure it is fact the lower. I've seen a code definition in my AE manual so it should have a soft code.

[md18]

Wait, so if you have dual alternators and the "primary" one fails then the secondary one won't power the truck? That seems kind of pointless.

[bigcountrysg]

Originally Posted by md18

Wait, so if you have dual alternators and the "primary" one fails then the secondary one won't power the truck? That seems kind of pointless.

The dual alternators work together. Doesn't matter which one fails. If one fails the other will work to get you wear your going. But you will stress the alternator out.


The two alternators should be wired in series.

[ABoyAndHisToys]

From what I understand the ambulance package with dual alternators is only to allow for additional components. So I'm assuming the 2nd one just helps the primary. At least I hope. I do know that when my primary went out months ago I made it maybe 4miles before the batteries drained down.

[dleopard19]

if u dont have an abulance i dont see where it would matter, all i know is if ur alternator does give out (if u have just one) i made a 3 hour trip on my batteries alone but i do not recommend that

[forddieseldoctor]

Originally Posted by bigcountrysg

The dual alternators work together. Doesn't matter which one fails. If one fails the other will work to get you wear your going. But you will stress the alternator out.


The two alternators should be wired in series.

They are wired in parallel not series. Usually if one goes then the other one is not too far behind. The system is designed that if one goes out that the other one will power a truck with no high current draw add-ons i.e. big lights or a big inverter. If it wasn't charging at all previously then it's very possible that both of your alternators were bad and the one that you replaced failed prematurely.