91 marq lights dimming at night

when i stop at a red light with my lights on all lights dim down to almost nothing. what could be the culprit basttery, alternator, something else?

thanks

Sounds like the Alternator but you need a Charging check to see for sure.

Most likely alternator. Could be bad battery connections. Get it checked free at your local auto parts dealer.

Yerp to both the above answers.