1996 F-Superduty (F-450) w/ 7.3 Turbo - after driving at night time, turn off head lights, body lights stay on... Is that the headlight switch malfunction, or some thing else??? I can turn off the body lights by disconnecting the batteries... Weird... I have never seen this before....

 

Disconnect the switch. If the parking lights go off, switch is faulty. If they still don't go off, there's a short/sneak circuit going on somewhere.

When you reconnect the batteries, do the parking lights stay off or do they come back on?

 

yes, they stay off

 

Hmm, that usually suggests a relay getting stuck closed, resetting when power is completely removed. But neither the parking lights nor the headlights have relays in the circuits, not in the pickups anyway. F-SD might be wired differently. Are there any aftermarket lights wired into the parking lights? Commercial bed with side/perimiter lights?

 

What do you mean by body lights?

 

I've been assuming (?) "body lights" means the parking lights.

 

I thought so too. Maybe the truck is Canadian though and it the head lights IDK.

 

Yes, the wrecker body has 3 "MARKER" lights on each side, and then on the lower tail board 4 brake / marker lights, 2 aft tail lights, and 2 more s/t/t in the light bar - best I can tell was wired correctly, not too long ago we rewired the truck body, and even then was having the same issue, but wasn't being problematic, like now killing the batteries if left unattended....

 

 

Well try the disconnect-the-switch trick first. Did the wiring for the additional lights include any relays?

 

K... Will try, need to get hands on some tools, and get to the switch, as far as relays - none installed, upgraded 6 of the lights to LED, rest are 1157 or 1156 bulbs

 

No, it's not hijacked, we are asking each other questions to help resolve the issue.

Which 6 did you upgrade to LED style? Brakes you can't do LED's unless they have the associated load resistors due to a PCM pull up resistor. This would cause all kinds of lighting issues.

 

LEDs won't cause any lighting issues. The light switching is purely electromechanical; the PCM does NOT control the lighting. The only PCM-related effect of using LED brake lights is that the PCM can mis-interpret the load, and "think" that you're pressing the brake pedal when you're actually not (for example, when you hit one of the turn signals), and will interrupt the cruise control and will unlock the torque converter on automatic transmission trucks. Moreover, the PCM isn't tied to the parking light circuit at all; it can't magically turn on or keep on any exterior lights.

 

Ok.. Sorry... Got confused with Canada crack...



OK.. Here are some pic's...


HAD 6 of these - 3 on each side 2 amber & 1 red

REPLACED THE BEE HIVE WITH THESE LED Lights




ON AFT ( OR UPPER SIDE REAR ) ARE OEM Jeep TAIL LIGHTS with 1157 - LEFT them alone, just made sure where hooked up right



AND then from the light bar - REPLACED the OLD BEAT UP DOT LIGHT STRIP CLUSTER TO LED, and installed new guts in the 1157 bulb sockets in the light bar...


HAVE NOT BEEN ABLE TO TEST LIGHT SWITCH, BEEN BUSY TODAY...

 

OP did not post which (6) were changed to LED's. I do fully understand the PCM pull up resistor and brake light issues with leds's and was addressing the possibility it was the post led light replacement causing problems.