Santa Fe (CM - 2007-12) :: 2010 V6 Can't Start / Clicking Noise With Dimming Lights

Our 2010 Santa Fe SE V6 just developed a problem where when we turned the key, the car wouldn't start, and there was a loud clicking sound during start attempt. Battery tested 100% OK.

This often points to a starter problem, but a telling symptom was than the headlights would dim, almost going out, along with the dash lights and most any other lamp. If it was just the starter, unless dead short, this associated dimming would not happen. I also put a volt meter on the battery and watched battery voltage during cranking attempt, and the voltage showed minimal drop, so once again the battery was not the problem.

Traced the problem to the ground strap from the battery which terminates to the driver side front wheel well. Two bolts hold the strap to the wheel well, and they are oxide coated and the contact point on the wheel well is painted. This means all the current returning to the battery is essentially passing through the bolt threads and cap where the oxide has been scratched enough to be conductive.

I sanded underside of the bolt heads to remove oxide, sanded the ground strap itself which seemed to have some sort of clear coating, and sanded the paint away from the wheel well where the strap makes contact. I didn't have star washers, but if I did they would have been a good addition.

Car now starts with no problem.

I am concerned with the possibility of corrosion under the strap where I sanded away the paint, but will monitor this. I think the contact between the strap and fender wall is tight enough with the two screws to seal out moisture and oxygen.

I am also going to locate and check any other chassis to engine ground straps so I don't have any new problems in the future.