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. I have the same issue. I have replaced the alternator twice now, both Duralast alternators. I found the exact same wire with discoloration and removed tape. It doesn’t look like the insulation was completely worn through though. I also pricked the wire with a multimeter and got a twelve volt reading. With the wire plainly not touching anything surrounding it, I still have a battery light on and am only getting a twelve volt reading! I am lost! Please help!

  2. Sparky,

    I have an 03 EB Expedition with the Charge light on which just started today I checked the wire in the photo and no issues there. I then turned on my radio, lights, A/C etc…, without the engine running to see how fast the battery would start to deplete, seemed normal. I then started the engine and the battery level went back up so it seems the alternator is working. Any ideas what I should try next?

  3. My 2003 Expy also had the chafed wire at the AC tube. My symptoms were intermittent battery warning light and audible alarm at low speeds. Thanks for the help!

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