My F350 6.0L diesel won't start. It fired up fine this AM and I drove it to church. When leaving church, it cranked OK and after about 50 yds. It died dead as a doornail. When I attempt to restart all the lights come on, the start indicator goes out and it turns over but no ignition. Almost 1/2 tank fuel. Battery OK. Any ideas? Thanks, Clyde

If warning lights (e.g. battery, ABS, SRS, or others) start appearing in concert with one another on the dash, immediately suspect the alternator. Most auto parts stores will test alternators for free. I would remove and fully charge both batteries too--most auto parts stores will also do this for free. Be sure to clean the battery terminals and connections.

If I'm right, and the alternator is the problem, all you really may need to do is disconnect the negative battery cable, remove the 3 cover/through-bolts on the back of the alternator, and replace the regulator/brush holder assembly. This is a very easy job and will save you a bundle.

If it's not the alternator:

. Test all under hood and under dash fuses with a test light or multimeter.

. Check for codes.