I've never had this happen before. I helped a couple guys jump start thier Toyota 4Runner today and stupidly let them hook up thier end of the jumper cables.
I was very clear in asking twice that they had the RED clamp on the positive side before starting my Jeep.

Well they didn't. Jumper cables started smoking within seconds and I immediatly shut the Jeep down and pulled the smoking hot cables off my Jeep.

It's 70 and sunny so I can't tell if all my lights are working yet. What are the chances the hippies fried something on my new JK???
Anyone have this happen yet?

Guess the lesson learned here is do everything yourself, don't trust anyone with your rig and for god sakes never ever ever let anyone hook up thier end of a jumper cable.

 

I am sure someone will come along and give a better answer than my guess, but since you had the starting battery, and the power was flowing from you to them, you are probably lucky and got off ok.

 

yetibear is correct. Since they had the dead battery, they are screwed...royally. You will be completely fine. This happend to someone when i was jumping them with my big Ford...RIP Anyway, they probably had some wires fried etc...basically its going to be expensive depending on how far it went.

 

I have always had a hard and fast rule when it comes to jumping people off if "I" have a vehicle with an onboard computer. I DON'T DO IT. PERIOD. It only takes a static charge to fry your ECM. That's why I have always recommended "jump boxes for computer controlled vehicles, and even then , it's not foolproof.

 

If you are concerned go by an auto parts place and have them at least test the Battery and Alternator and hope things are good.

 

I won't jump people either it's just too risky now with the computers etc.

 

Just goes to prove you cain't breed a Toyota and a Jeep together Also proves the old car business adage- ''Hell I knowed you was an Idiot when I seen whut you was driving''...

 

I would suspect the alternator would be potentially damaged before anything else. If it is charging OK under load, I would not worry about it. (I've killed a few alternators in my time - though not by connecting the terminals backwards. Now, 24 volts, on the other hand...)

 

That sucks! I had this same thing happen with an old Chevy truck once. My truck jump starting a dead vehicle. I let the other owner hook up his side. Like you, I even said multiple times Red on Positive. Sure, sure he replied......
Needless to say I will never let anyone hook up jumper cables to my vehicles again. Cost me an external voltage regulator at a time when I was in college and really did not have the money to spare.
No more mister nice guy. Neighbor recently asked for a jump. After testing his battery, to see if it was at or better than 12.5 volts, I had him remove his battery. I hooked it up to my charger and had him come get it after it was charged

 

i believe now days they have a inline fuse to stop any reverse charge before hitting the ecu/ecm and frying your system.