2003 Ford Expedition, Charge Light On, P0620

This 2003 Ford Expedition came in with the complaint that the alternator had been replaced twice and the charge light light indicator was still coming on. The shop that had installed the alternators had called in desperation as their customer was becoming quite upset. They also stated that the light may stay out all day or only about an hour. When their customer showed up with the vehicle I was a little surprised. The shop usually sends vehicle on a flat bed and drops them off. Time to try and make everybody happy (except Me) while the customer waits(I was trying to eat lunch). I did a quick visual inspection of the wiring at the alternator and everything looked okay. I checked codes and found a code P0620 stored (alternator problem). I then looked at the wiring leading to the alternator and I saw this telltale sign. A wire with discoloration against a metal object.

The metal object in this case was the a/c low pressure or suction line that runs along the lower edge of the battery. I lifted the wiring up and could tell from the amount of discoloration that I might have found the problem.

Yep there’s the problem. I removed some more tape. Wrapped the damaged wire. Rewrapped the harness.

Installed some split loom and cleared the codes. Rechecked the system and all was okay. Back to my lunch.

42 discussions on “2003 Ford Expedition, Charge Light On, P0620”

  1. 2003 Expedition, the battery light has come on as most have described here. Last night the light was flashing and bells and whistles were blowing, the Overdrive light also came on. As my wife pulled into our driveway, the vehicle began sputtering and finally quit. The battery was drained and the vehicle could not be restarted until the battery was charged.

  2. We are having the same problem. 03 EXP EB. Had the alternator checked and it shows good. Battery is good. Fuses all good. Gauges show battery charging but then the alarm comes on. Checked the wiring in your explanation and no problem there. Don’t know which way to go now. Some sites indicated it could be a PCM problem. Thoughts?

  3. Are you checking voltage at the battery or at the alternator output stud? With the key off is there battery voltage at the alternator output stud? If not locate and replace the blown mega fuse. If you do please confirm the year and engine size of your Expedition. Is the check engine or service engine soon light on? If so what are the codes?

  4. My alternator is not charging my battery. The light is on. I’m only getting 12V at the battery and at the alternator hot terminal. I have replaced the alternator with a Duralast with no change. I then took the alternator back and had it checked, checked good. Then, they swapped it with another and checked it, check good. I installed this second alternator and problem still persists. I found the same wire with discoloration and removed the tape. The insulation was not worn all the way through. I also turned the vehicle on and pricked the wire with a multimeter lead to find a 12V reading, the other wire reading about eight and a half. With the wire hanging away from all other parts and the vehicle started I still only get a 12V reading from the alternator, which is obviously just being pulled from the battery. Any ideas? Please help, I’m lost!

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