Battery Light

[MurderMarauder]

After purchasing my marauder from a family member the battery light has been on and stayed on after about 20-30 seconds of the car being started. I was told by them that there was an issue with a communication wire between the battery and the alternator. I however had the battery and alternator tested by o’rielys and auto zone and they both said that the battery was good but the alternator output voltage was low. I then got a new alternator from o’rielys ( I got one that is a Ford 4G- Marauder specifically) but the battery light remained on they also said the battery was still good. After taking some readings I was still getting the 13.5 volts to the battery as I was getting with the old alternator. I then have recently been having some issues with my starter as when I try to crank over the car the starter makes a thud noise and if you keep trying for 10-20 seconds the thud keeps happening but then after that time the car will turn over. I don’t know if this is a similar issue or if my starter is going out or both separate issues. Looking online some talk about problems with the PCM or signal wires or possibly relays or fuses. I’m not the best with these type of issues and just looking for any general advice before I take it to a auto electric shop. Thank you

[Mr. Man]

Check all the main power delivery wires for corrosion. Sometimes its hidden up into the shielding.

[MurderMarauder]

Thank you for the response, it’s either my voltage regulator is bad on both my old alternator and new one or I have a more serious electrical problem and that may explain part of my starter issues.

[RubberCtyRauder]

Was this car driven in winter? I see your location of as Michigan.. corrosion on battery cables like mentioned up and under the coating is a distinct possibility. Or at starter or a ground

[MurderMarauder]

I appreciate the reply, I got the starter rebuilt and found a broken communication wire to the alternator to explain the battery light, everything seems to be fixed now.