burnt ground wire..........

Here's an interesting one. 98 Windstar 3.8. Was checking my air conditioning today, had the van running for maybe 5 minutesin the driveway while I was looking and feeling around under the hood, and the secondary ground wire that goes from negative terminal of the battery to the chassis, got so hot the insulation burned off the wire. Here's what I know.......
- wire only heats up when a/c is running
- the wire is not original. Part of the original is still attached to the body, but it has been cut at some point in time and two lighter gauge wires spliced from it to the negative battery post (pretty light, probably 16ga). Not sure if it originally even went to the battery post.
- I've had the air conditioning on before while driving and there were no signs of the wire having been hot before today.
- No fault codes, no other signs of anything wrong, besides not having any cold air (never has worked since I got it a few months back)

Anyone have any ideas? Is there even a ground wire going from the negative termial to the body, or has someone eliminated or bypassed something on me before I got it. I know the two spliced in wires should be heavier gauge, but what would be causing such a high current to be going to ground from the neg battery terminal?

Headlights, Blower motors, WIndow defroster, Stater are all high current items.

All current will return to the battery via the ground wire. Not sure of the gauge but 16 is small.

thanks for the reply, but does it return via the main ground cable or through the body via this secondary cable?



Headlights, Blower motors, WIndow defroster, Stater are all high current items.

All current will return to the battery via the ground wire. Not sure of the gauge but 16 is small.