On my 1991 f250 (4X4, 460 ci), the parking lights stay on after I turn the headlights off. I have to disconnect the battery terminal to get them to shut off. They stay off after i reconnect the battery. I've replaced the headlight switch and what I think is a switch relay under the hood. Nothing is helping. Any suggestions? Thanks!

 

Do you have dual wheels?
If so is this the side an and rear body marker lamps only that say on?

 

F250 shouldn't have dually fenders.
Does the truck have some "extra" wiring done to it that might be screwing up? Did someone put a relay on the parking lights and tie the control wire in wrong? Thus making them stay on even if the headlight switch is turned off. Once the battery is disconnected, that drops the power from the relay coil and turns the lights off.

 

It's not a dually and I'm unaware of any additional wiring, but I am the 3rd owner and something may have been done that I can't obviously see. I just took a closer look and it's the parking lights AND the tail lights that stay on after turning the headlight switch off. Another thing I'll mention which may not be related is that for about a year my e-brake indicator light has been constantly on whether the ebrake is on or not. Thanks for your suggestions and questions. Still scratching my head...

 

mine does that also but if I turn my headlight switch to dim the dash lights the other park and tail lights shut off. does your dash light come on as soon as you turn your ign switch on?

 

Nothing like that happens. But here's another possible clue--When I disconnect the relay from the plug (under the hood), everything works fine. This is why I thought the relay was bad. I would just leave it disconnected and be on my merry way if I knew I wasn't disconnecting something else. There are 4 wires going into the relay switch.