Why would the cable to my alternator burn up and now that I replaced it and a new battery, it won’t charge
What is your question?
I was driving home from work and the battery light came on, my speedometer would go to 0 then max out at 140 , and keep doing that. I just made it home by coasting it down the street. I looked and saw the cable coming into the alternator was burnt off. So I went and got a new one and new battery. And nothing , no charge. So I replaced the belt, tension pulley and pulley on top. Checked the wires they looked a little shitty at the terminals, so I replaced the end at the battery and at the starter. Still nothing. I used a multimeter from the positive on my battery to the alternator and it’s hot. It read 12.89 volts. I checked the fuses . There all good. So I’m pulling my hair out trying to figure this out. Please if you know anything else to do let me know. Thank you
What makes this problem better or worse?
Nothing , it won’t charge the battery
How long has your 1999 Ford Ranger had this problem?
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Hi, this is Bo, an auto expert on RepairPal's Car Genius team!
When an alternator cable burns up, it’s usually the result of excessive resistance, a short circuit, or an overloaded circuit. Now that you’ve replaced the cable and battery, and it’s still not charging, I’d suspect an issue in the alternator itself, the voltage regulator, or possibly in the charging system wiring.
First, make sure your alternator is functioning. Even though it’s receiving voltage, if the alternator’s internal components or the external voltage regulator (if separate) are faulty, it won’t generate the output needed to charge the battery. Use a multimeter to check alternator output at the battery with the engine running—it should read 13.8-14.4 volts. If not, the alternator is likely toast.
Next, inspect the alternator wiring harness and ground connections thoroughly. A fried cable may have caused unseen damage to surrounding wires or connectors. Look for melted insulation, corrosion, or loose connections. Also, ensure the alternator’s fusible link (if your Ranger has one) is intact—it’s a common failure point during electrical overloads.
If all checks out and it still won’t charge, the issue could lie in the PCM (which controls the charging system in your Ranger). A scan tool can confirm if the PCM is properly commanding the alternator to charge.
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