Won't run without battery connected...

[onebad7up]

My wife called me this morning at 5:00AM to tell me that she was broke down on the side of the road....perfect start to a Monday morning.

After driving for 10 minutes, the warning indicators for all of the various systems started to flash (ABS, AWD, Transmission, etc.). She pulled over and the truck finally shut off on its own.

I was able to hook up a helper battery and it would start and drive. I pulled it over to a parking lot and pulled the codes. P110F, P115D, P1890 and P1551. It looks like these are random codes so they likely came on because of the low voltage condition. No way all these different items failed at once.

When the truck was running I tried to disconnect the battery terminal in order to check the alternator. The vehicle died immediately.

This leads me to think it is a bad alternator, but I just had it checked at recently after installing a new battery.

Does anyone know how I can verify that it is an alternator and maybe not something like the voltage regulator?