the problem i got is some thing is killing the battrie. or the alternator is not charging. alternator is new. batt is new . done the old stick a wrench to the pulley test and the alternator is not magnetic when running. i have 3 wires running to alternator but only 2 where hooked up. there is a white wire not hooked up. never been hooked up since i have owned the truck, one more question i have is i have a aftermarket tach in the truck that i didnt install one wire runs to the negative side of the coil. i not sure this is wright i was thinking it should go to the possitive side. the coil is running around 9 volts on the possitive side and 5 volts on the negitive . oh yeah i have come to call the truck CHRISTINE becouse i think it is going to kill me before i get it fixed

 

Wrench to the pulley? The "trick" is to put a wrench or screwdriver to the bearing on the backside of the alternator. If it is magnetized then the alternator should be working. Of course this won't tell you what the amps are coming out of the alternator.

The negative side of the coil is the proper side for tach wiring.

Try this, close both the doors, make sure no accessories are on. Remove the underhood light and take out the dome light. Run a test light between the positive battery cable and the positive post on the battery. If the test light lights up you have a draw somewhere. To figure out what circuit has a draw disconnect a fuse one at a time from the fuse panel till the test light goes out. Once you figure out what fuse went out then search out your short in the wiring.

 

checking the alternator with a meter the most i got out the back was 13 volts that was with battrie still hooked up. truck running like its not getting enough voltage to the ecm dropping the whole time like the truck is running off the battrie not the alternator. the wrench works either way on heavey equipment i assumed it worked the same on passenger cars but i have done both sides and it has no magtisam either side

 

oh yeah ranger got my 35s and lift on my truck thanks for your help in that

 

ok checked the wires with test light got nothing threw the light pulled the battiery cable off while the truck was running and it died as soon as the cable last connection the alternator is bad but what does the white wire go to

 

White wire is connected to the stator lug on the alternator and from there should tie in the the "S" post of the voltage regulator.

Josh

 

does it need to be hooked up for the alternator to charge?

 

Someone please explain to me why trying to get something magnetic to stick to the alternator should mean anything. The alternator works by changing the magnetic field through several turns of wire by rotating magnets. Change in magnetic flux is what causes alternator output. The alternator simply having magnetic properties tells you nothing. There are magnets in it to begin with whether it's spinning or not.

DO NOT REMOVE THE POSITIVE BATTERY CABLE WHEN THE ENGINE IS RUNNING. The voltage regulator sees this as open-circuit and causes the alternator to go full-swing. This can fry the ignition module and any other on-board electronics such as a stereo or CB.

weldworks - I'm sorry man, but I have almost no idea what you're trying to say because of your terrible spelling and grammar. We are very eager to help you, but if it takes longer than 30 seconds to get the jist of your problem, you're not going to get a lot of help. Are you having trouble with the battery being dead when you go to start the truck, like it's not charging? You've stated some things you have tried, but you haven't explicitly stated the symptoms (in a form that I can understand, at least). Please do so and then we will go from there.

 

the problem i have is with the truck running. the battery will go dead.i have a white wire that runs with the alternator wires to the alternator but is not hooked to anything and has not been hooked since i have had the truck. i drove the truck about 30 miles sunday, turned the truck off and had to be jumped off. on the return trip truck when to running rough after about 15 miles. like it was not getting enough voltage to the ecm. i have check the battery cables like ranger said with test light andthe light did not light up so i asume the alternator is bad. the theory of the magnetic feild in the alternator is that it will magnitize the bearing on the back of the alternator. sorry about the spelling i am currently hooked on phonics.

 

Much better; here goes:

1. Rough running is not attributed to low voltage at the ignition module (what you're incorrectly referring to as the ECM). The module will either power on, or not. There is no in-between state. If there is insufficient voltage to the unit, the power transistor cannot bias and the unit will not fire the coil. While low electrical system voltage can cause rough running problems, it's not due to the ignition module not getting enough "juice."

2. ranger429's test was not meant to test your alternator; it's meant to test to see if you have a parasitic draw on your battery. If you have something like a glove box light staying on and drawing current when you shut the truck off, this test will identify it. You cannot conclude anything about your alternator from this test. No light is a good thing; it means nothing is drawing on your battery that shouldn't. One thing to mention that wasn't clear in any of the above explanations is that you must do this test with the test light placed in series with the battery cable. That means with the truck SHUT OFF, disconnect the battery cable and bridge the cable to the battery with the test light. As ranger429 said, this must be done with loads that you already account for disconnected, such as the dome light. Another thing I must mention is you should do this test with the negative battery cable, not the positive cable. From an electrical standpoint, doing the test with either cable will produce the same results. However, it's a safety issue. Never remove the positive cable with the negative cable still installed. If you ignore this warning, your wrench could short on the fender while you loosen the positive cable, creating a spark, which can blow up the battery due to the fumes surrounding it. As such, do this test with the light between the negative battery cable and the negative battery post instead.

3. I do not agree with the "theory" about magnetizing the alternator bearing having anything to do with the alternator's throughput. While I agree that the magnets inside the alternator itself can exert force on nearby magnetic objects, this property has nothing to do with the functionality of the unit from a circuit standpoint. Look up Faraday's Law. Many people seem to think that the alternator "magnetizes" by turning and this couldn't be any further from the truth. The alternator is always "magnetized;" it's the movement of the magnetic field through coils that generates the current.

4. I'm pretty sure the white wire you're talking about is the stator signal of the alternator. Before I can help you any further, I have to know if your truck has an actual ammeter on the dash (with a needle between D and C) or simply an "ALT" light.