Stalling 1999 Tahoe

The Tahoe (5.7l 4x4) stalled on the wife today.

She started it and then went to put it in gear and it died. NOTHING. No crank, no power. (She did say there was a clicking noise like a turn signal noise for a few seconds afterwards)

15-20 minutes later it started up and she drove 30 miles to pick up the kids. She left it running and then put it in gear and it died again.

Any help out there with this one. I've been a ford man for years and just bought this used vehicle two months ago with 96,000 miles.

Thanks.

If she is hearing a clicking noise and the engine will not turn over (starter won't engage) I would look at the electrical system...first place is look to at the positive battery cables for corrosion.

Thanks.

I arrived on scene and after a few minutes noticed that the postive cable was loose. Oddly enough when the cable was not connected the engine shut off. With other cars I had used the method of disconnecting the positive cable to determine if I had a bad alternator. Upon closer inspection I noticed two positive cables. One must be to the alternator in some fashion. It looks strange to have these two cables connecting to the battery. It is also likely the reason the cable had come loose.

There is a mounting for a second battery. How many of you have two batteries?

Thanks.

I arrived on scene and after a few minutes noticed that the postive cable was loose. Oddly enough when the cable was not connected the engine shut off. With other cars I had used the method of disconnecting the positive cable to determine if I had a bad alternator. Upon closer inspection I noticed two positive cables. One must be to the alternator in some fashion. It looks strange to have these two cables connecting to the battery. It is also likely the reason the cable had come loose.

There is a mounting for a second battery. How many of you have two batteries?

The second cable runs to the UBEC (underhood fuse box) and powers the truck..removing the cable from the battery removes all power from the truck.

Thanks.

I arrived on scene and after a few minutes noticed that the postive cable was loose. Oddly enough when the cable was not connected the engine shut off. With other cars I had used the method of disconnecting the positive cable to determine if I had a bad alternator. Upon closer inspection I noticed two positive cables. One must be to the alternator in some fashion. It looks strange to have these two cables connecting to the battery. It is also likely the reason the cable had come loose.

There is a mounting for a second battery. How many of you have two batteries?

How does the two-battery configuration work?