Hi I'm new, I have a 91 150 with a 5.0. the trucks runs great. But i have a drain or draw on the battery that makes it not start.I can put a charger on for ten minutes fires rite up,and will run all day starting and stoping.I have check everything just can't figure were the draw is coming from,Any ideas thanks.

 

well if it starts fine after a charge then make sure the alternator is charging the battery. and have the battery tested.

 

I just put in a new battery yesterday,and had the altenater tested thats new starter new sel. new. it will start for a couple days because its new for now.just don't get it cables are all good and connections as well.I am lost

 

You need to hook an ammeter in series between the battery and the ground cable. Disconnect the battery ground, then attach an ammeter (use one with a 10amp scale), positive ammeter lead to the battery cable and negative ammeter lead to the negative battery post.

Make sure the doors are closed and all lights are off when you do this.

By the way, confirm that your interior lights DO shut off when you close all the doors - if they don't, you've found your problem.

If everything is working correctly, you should see only a very small reading on the ammeter, something on the order of 0.05 amps I think. Anything much higher than that means you DO have something in the truck that is drawing power from the battery.

If there's a higher draw, you have to start pulling fuses one by one, until you find one that causes the battery draw to drop back where it belongs. When you do, you've found the component that is draining your battery. This can be a very tedious bit of troubleshooting - good luck.

- Jack

 

thanks but hate to say i pulled the fuse's one at a time to see if i got spark putting them back in would showw a draw i got nothing.someone told me to disconnect the neg. cable from battery a put a light tester from cable to post i got a dim glow. open the door and really lites up from the door being open push in the button go's dim. i just banging me head trying to figure were the juice is going. thanks

 

tonight just make sure none of the lights are very dim(inside and outside). something must be shorted to power. do you have any kinds of accessories? and what type of alternator did you get? when did it start to draw? and what have you done right before it started?

 

Lift the hood and find the alternator. Look for a shielded wire that is bolted to the top of the alternator, usually. Disconnect the wire. This is the hot wire from the battery. If it sparks or jumps electricity, the alternator is toast. The final diodes are toast allowing juice to flow back thru the alternator to ground. You do not have to have the key on for this test. This is a common problem with Ford alternators. DO NOT BUY a rebuilt unit. Rarely do they check the diodes when rebuilding, only the output. Buying a rebuilt will just about guarantee the same problem. Most auto parts will test your alternator for output but not for the final diodes as they have to get inside one to check.

 

My dad had this issue on his 88 town car a couple of times.

 

to answer mitts question i bought it from autozone and i try that other alt.test tomm.Come to think about its done that since i got the new one. i just figured it was new so it could'nt be bad.but i bought junk parts from them before thanks to all i'll check it out in morning and get back too you.

 

sorry about that MATT,

 

crash594, i look at the alternator it just has to plugs one on side and 1 towards the top. it fired up just fine this morning but the new battery only been in for 2 days.

 

should you have any juice going threw the neg cable?????

 

Have you tried Labnerd's suggestion ? That's easy enough - and pretty damn smart.

Jack gave you the run down. You need to do these things and if you don't understand how , ask . Don't ignore Matts or anyone trying to help. These guys know there sh^t. Concentrate on what they are telling you and you'll find the problem. - All are great replies here..

 

ok i'll try it in the morning thanks tou you all i'll let you know where if not a parts house should i get one or have it rebiuld and make sure they change the final diodes???

 

hello guy's i took the altenator off and had it tested they said it was all good,so now i'm wondering do's that truck have a voltage regulater on it i remember the the old vec. had them? the volt. gauge in the truck reads always chargeing instead of being rite in the middle???whats up with that??? thanks for all your ideas but lets try to figure this thing out.Or how to do it i'm just banging my head.