Temporary loss of electric power

after going through a puddle the lights dim, the wipers slow for 20 to 40 seconds,then everything goes back to normal until the next puddle. the serpentine belt is good with no squeals. what part of the system should i focus my efforts? alternator, spark plug wires, applying dielectric grease?

1998 mercury grand marquis, 4.6 liter

any suggestions would be appreciated in trying to solve this problem

Sounds like a glazed serpentine belt to me. Put a socket on the alternator pulley and attempt to rotate the alternator against the belt.
It should be difficult or impossible to move the pulley. If it rotates somewhat freely the belt needs to be replaced.

With serpentine belts, they do not always squeal when slipping like the old V-belts would.

thanks so much…i’ll give it a shot

See if you can duplicate the effect of the puddle with the garden hose,try to narrow it down to just what is happening when things get wet.