99 f150

HELP!!!!!!! I am trying to figure out why my new battery and new (rebuilt) alternator are not working.

I found some help on this site before and am hoping that I can get some more good advice.

I replaced the batt (very dead) and then the alt (tested bad at Sears (their new batt was bad too replaced) and Autozone) and the system is still not charging. I am bringing it back to Autozone to test their 'new' alt but could it be something else in the charging system?

I tested output with multimeter and am showing battery voltage only. I was getting the weird guage behavior and some strange relay clicking under the dash but that went away after new battery installed.

Any ideas?

 

-The relay clicking is because of the low voltage situation.
-With the engine running, feel the alternator and check if it is hot. It should be warm, but if it is hot, then you have a short some where in the system. If, while the truck is off for some time(a day or so)the battery does not drain, the short is probably in the 'post ignition relay' circuitry. Again, this is only if your alternator is hot to the touch. If the battery seems to drain while the truck is sitting or only the ACC is on, the short is probably prior tho the ignition relay and should be easier to find.
-Battery voltage only is bad(12-12.5V) while the truck is running, means your alt is not working properly for some reason Should be about 14v (or more if your battery voltage is low).
-If the alternater that you purchased does prove to be bad, I would demand another battery also. Once you drain a battery to the point where it won't start your truck, you have ruined the battery. The life of the battery will have been shortened and becauseof sulfite crystal build up, it may even shorten the life of the new/replacement alternator because it will force it to work harder.
-My opinion, never buy your batteries from Autozone, they don't know how to maintain them. There may be exceptions at some stores, but I havn't found one.
-I alwayse try to replace batteries and alternators in tandum. Most batteries last for 5 yrs so the added expense of an alternator every 5 yrs aint bad. An old battery can shorten the life of a good alternator. If an alternator goes out and drains your battery, it will ruin it.

 

Thanks for the help. I'm going out in a few to try and find the "real" problem.

The battery is from Sears. I've always had good luck with them, except this time! The first batt I got from them was very bad.

I figured the relay click was due to low voltage. Thanks for the confirmation.

Now if I can just confirm where the damn problem is!

 

I generaly like the Sears batteries also. I know they got some bad press a few yrs back, but I have alwayse had good luck with them. Let one drain for 14 hours once by accident, charged it up and it went on to last another 6yrs. Interstate batteries are great also. Stay away from those Autozone batteries.

 

Check for a blown fuse in the maxi fuse box under the hood, and make sure the one for the alternator is good. Good luck.

 

Well, both alts tested good at the zone and since I installed it I own the new one... oh well but its still not charging in the truck.

Now the fun begins.
Where is the fuse box under the hood? I'll look in the morning.

I gotta get the chilton or hayes! Any ideas on which is better?

Anyone have the wiring diagram? Thanks for the info so far, wish me luck!

 

Since you have a newer truck, I think you may have the alternator with the regulator built in. I would check the output wire. Follow it along and see if you find a fusible link in the wire. It could be burnt out.

 

It could be just a damn fuse! I found the other fuse box in the engine compartment. WHY would they put one there???!!!! What were they thinking???????

I'll let you know tomorrow if the fuse fixes it. I got the Haynes so I have somewhere to start looking!

Thanks again.