electrical problem

when driving my 1994 f150 with a 302 charges ok but when you stop the lights dim guage drops way down, wipers just barely run. put new battery cables on,ground is ok, any ideas?

clean all ground wires and if it is still the same have your altenator checked

Like above said have your alternator checked. Charges ok you say so you've never had to jump it or charge the battery and it turns over good when starting? Are the wipers always slow? If so I'd check the power connections coming to the wiper and headlight switch, if the alternator is infact good then you probably have a problem with the power wire that feeds the headlights and wipers--that or bad grounds for both.