Why does my 92 sedan deville lose power when i cut on the headlights or the a/c? on 1992 Cadillac DeVille

When i turn the headlights or a/c back off the power goes back to normal and i am able to gain speed

by in Fort Worth, TX on July 10, 2013
1 answer
ANSWER by , July 11, 2013
poss bad has low voltage and or alternator output is low.