Isuzu truck will not start if I run AC for a while. The truck runs great normally, but today 90 degrees + I ran AC. Drove 150 miles. After 10 minutes tried to re-start and all dash indicators flashed and then went OUT... nothing. Removed key... tried again... same results. Waited a while longer... flashing dash lights stayed on longer but nothing... waited again,. and as the flashing started, I immediately tried to start and success. Drove 100 miles to home, but turned AC off for final ten miles... shut engine off waited a short time... vehicle started like normal. What is AC doing to my truck??

Remove and fully charge the battery--it may be bad. Have the alternator tested--I suspect the brushes have worn down so far it's lighting up your dash like a Christmas tree. The A/C is draining a marginal battery and alternator.

On many alternators, it's easy to replace the voltage regulator/brush assembly for around $20.