[DocDirk]

My 533 BB Ford runs about 190 degrees average, depending on the usual weather and speed factors. I usually drive daytimes but recently came home later and when I turned on the headlamps I noticed an immediate slight rise in the temp gauge, about 5-10degrees, then gradually continued to rise to about 220 (ambient temp about 90 degrees F). Since then I've tried the headlamps at other times and the engine temp does exactly the same thing regardless of the ambient temp. I have a huge 4000 cfm shrouded fan pulling through a large aluminum radiator.... 140 amp alternator, high end Prima battery and no headlamp malfunction when operating... could they possibly be drawing enough to reduce current flow to the fan with resultant reduced cooling efficiency? Even at highway speeds the temp doesn't return to "normal" and turning the headlamps off results in a quick return to normal temp readout on the dash. The voltmeter moves from charging to slightly in the red when the lights are on. They're standard stock sylvania nothing-special lamps. Or am I looking at some odd wiring problem between the gauges? Unfortunately for me, ekletrikelty is one of my weak suits...

Thanks!

Dirk