I took my battery and alternator (rebuild) to autozone and they tested and both are good but my battery is not getting charged by alternator.. when my car its on i took one battery terminal and it shuts off.. but alternator is good. i guess i have to check wires? or fuses? where do i start? ohh i forgot to say, my car its a stick shift so when battery is dead i just ask for a push and turn the car the hard way u know by putting in first gear and turn it on that way... and it stays on, but lights and radio wont work. Any advice? Thanks
First off, disconnecting athe battery while the engine is running is the quickest way to damage an alternator. Unlike the old DC generators, the alternator needs the battery in circuit to protect it against voltage runaway.
If the alternator has been bench-tested and seems to be functional, I would start by verifying the related vehicle circuits. Witch a DC voltmeter, start out by measuring the voltage at the alternator's output terminal, the heavy black/orange wire. It should be full battery voltage. If it is anything less than battery voltage, you must determine why. Some things to look at are the gray 12-gauge fusible links A & B, and the various splices and connections in the circuit (see diagram below).
Next, disconnect the voltage regultor harness plug from the alternator and check the voltage at the wiring harness regulator plug's "A" terminal connector - the yellow/white wire. It too should be full battery voltage. If it is anything less than full battery voltage, you must determine why. In this case, look at the 20-amp ALT fuse in the battery junction box, and at the various splices and connectors in that circuit.
Then, turn the key switch to its "RUN" position and measure the voltage
at the wiring harness regulator plug's "I" terminal connector - the light green/red wire. It should be somewhere between 8 and 12 volts. If there is no voltage present, check Fuse 5 (15 amps) in the main fuse panel and the various connections in that circuit.
The final test is to measure the voltage between the batterty positive terminal and the alternator housing or frame. If it is anything less than full battery voltage, check the alternator mounting.
One other thing that I just thought about... When AutoZone tested the alternator, did they just do a maximum output test? Or did they also verify the function of the voltage regulator? You can easily do a functional test called a "Full Field Test" yourself. This test requires that the voltages I already described are correct, so it should be done AFTER the above voltage tests. Look at the back of the alternator and identify the two screws that secure the voltage regulator to the alternator frame. One of them will be labeled "A" and the other one will be labeled "F". The "F" terminal is the one that we are interested in for this test. With the alternator properly mounted and the engine running, connect a DC voltmeter across the battery. Now, note the battery voltage reading, and then use a jumper to ground the alternator/regulator "F" terminal. This can usually be done with a pair of needle-nose pliers, placing the tip of one side of the pliers against the "F" teminal and the other on the alternator frame. Now look at the battery voltage again. A functional alternator with proper battery voltages appled will show an increase over the previous reading -- up to 14 volts or more. If you get an increased reading here, the basic alternator is healthy and the problem is in the voltage regulator, which should then be replaced. CAUTION: DO NOT LEAVE THE JUMPER ON THERE FOR MORE THAN A FEW SECONDS TO AVOID POTENTIAL OVERVOLTAGE DAMAGE. DO NOT INADVERTANTLY GROUND THE "A" TERMINAL, AS THAT TERMINAL HAS A DIRECT BATTERY POSITIVE CONNECTION! If there is NOT an increased voltage at the battery when the jumper is connected, and if all of the previously-discussed supply voltages are OK, the alternator is defective.
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My money is on the alternator, just because it tested good does not mean it is, i had a 95 mustang that had a bad alternator that would "intermitantly" charge an when i had it tested it was charging but two days later it died completely. you could also check the cables themselves as well.
SOURCE: alternator not holding charge
you need to check your grounds... very good possiblity there is a bad ground.
SOURCE: battery not charging
check the fuses in the POWER DISTRIBUTION BOX under the hood, There is a 75A in-line fuse and #11 - 15A fuse see if they are good.... test your alt. loom for opens, and cables .....hope this helps...GL
SOURCE: 2002 F250 dash instruments are dead.
Check the fuse which controls the OD button also knonw as TCIL. It often blows from a short on top of the steering column
SOURCE: I have a 2002 Ford Explorer. I replaced the
i think under the hood in the fuse box there is a alt. fuse. it maybe a little 30 amp/green fuse. try that first. the older one used this.
SOURCE: Instrument panel went dead
Checked Every fuse in the fuse box (no small task).This includes #4 - Power point Instrument Panel, #14 - Day time running lamps (auto lamps doesn't work nor does auto lock), #27 - ignition switch run feed, #35 - Instrument Cluster, #41 - Instrument Cluster, #42 - Delayed Accessory, #45 - Ignition switch run/start feed, #102 - Door locks body security module, #103 - Ignition switch, #110 - Ignition switch, & #116 - Ignition switch. But I also check all other ones as well, they all register OK. AC panel & radio work. Turn signals work. Mileage does not work, trip computer does. So, basically, everything works except auto head-lights, auto locks, and the dash cluster (no MPH, RPM, mileage display, Fuel, Temp, Tran Temp, and Oil Pressure).
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