My automatic headlight fuse blows every time the headlights turn off. I replaced the main headlight switch, but it did not help. Could the light sensor switch in the dash be bad? Is there a relay somewhere that may cause this? Any ideas??? HELP!!!!
It's a 2002 f150 super crew, 5.4 engine.

 

No ideas, since you haven't divulged what year or model you are asking about.

 

Sorry, My truck is a 2001 f150 super crew, 5.4 engine. THANKS!!

 

if you could tell me what fuse exactly blows i could tell you what is wrong !the fuse number should be on the other side of the cover .

 

Fuse # 29 is blown.

 

that fuse is for your autolight sensor. i would replace it if i were you it's probaly shorted internally .are you sure it's 29 the 5 amp fuse? if it's that fuse the sensor or the circut is shoted to ground.if you have a multimeter check for continuity at ckt 474, orange with a light green tracer it's one wire located in under the hood on the driver front side. put one lead at fuse 29 (make sure it's a good fuse, or just pull it out and probe the connecter on the side that doesnt have batt. voltage.) put the other lead at the sensor connector and check for continuity if you have it. replace the sensor if you don't , follow the wire untill you find the short to ground, and just solderand shrink wrap it.That sensor is the only load on that circut ,so if it shorts out it will blow the fuse when you turn you headlights off.because you switch the relay and power goes to the sensor and that sensor only allows currunt to flow to the headlamps if it doesn't see light. the sensor it self is on the bumber in front of the drivers side headlamp first look at it and see if it's damaged most likly a o.e.m. part so you'll have to go to Ford for a new one.
p.s the spec for the sensor is 0.285 and 0.315 ohms.