My 91 f150 headlight switch does not turn on the parking lights at the first pull out slot but if you pull out alittle passed the setting as if you were to turn on the headlights they would come on. To make matters even worse. If you pull the switch completely out to turn on the headlights the parkinglights turn back off. Now catch this. If you push in the **** a hair or so as if you were turning off the headlights the parkinglights will then come back on with the headlights but will wiggle themselves back off after a few bumps.
I purchased a new switch and installed it but still have the same problem. I electrode tested both switches and they show no problems so I figured i would test the wires in the wiring socket that plugs into the switch and they also pass the test.
Pulling my hair out over this doesnt work either. Im stumped. Any help sure would be appreciated!

 

Sounds to me like its the switch. Are you sure you didn't pull a Billy and put the old one back in. Been there and done that.

 

Well, I am positve now that its not in the switch. Just purchased another new switch and still has to be fumbled the same way in order to work.
I have a Haynes book on my truck and studied the wire set-up. The only way I came up with in my mind was, inorder to get the parking lights on was to have it ride particially on the headlight positive within the switch. As if it were feeding off the same positive as the headlights. I wouldnt think that would be possible but its all i can come up with. Testing showed connectivity between the two terminals but couldnt find a positive wire within the two when I checked with a test light. I wish the Haynes book would go into more detail of whats pos and neg on the diagram. Unless it does and I not know how to read it. Thats possible. Anyone else have an idea of what may be causing this grimlin before I give up and just pay for someone to take away my headache?

 

Black with an orange stripe is power, I think for the parking lights. Tan with a white stripe is power, I think for the headlights. Both have power always. Brown is power out to the parking lights. Red with a yellow stripe is power to the dimmer switch. How was the connector on the back of the switch? They are usually black, melted and brittle.

 

The connector looked clean. No burns nor cracking. That was what I was hoping for, a possible short and a blown fuse. No luck with that. I plan on taking the wires out of the harness, checking and reinstalling them 1 by 1 tomarrow. There may be a bad connection on the pos terminal that leads to the parking lights. I appreciate the heads up on the color coding for the positive wires. Looking forward to getting at it once again tomarrow, just in hope to figure it out. The pos info will really give me a heads up on figuring. Ford wouldnt wire an inline fuse on such a thing would they? Scratch that" That would rule out the purpose of a fuse panel.

 

Black with an orange stripe is on a fusible link. Tan with a white stripe is on fuse 4, 15 amp.

 

Got it working right again.

Well, I didnt. I was outside working on it and saw a man outside the auto repair shop and asked him what I could use to clean the connectors with and he said pull match heads through them and the heads of the match will clean them off. Then he walked over and asked if he could give me a hand. Told him the problem I was having with my switch so he toke the tester off the seat and started testing the wires. Asked me to write down some color codes for him as he tested. Gave him the paper when he was done. He looked at it and started unpluging the wires and swapping them around. Had me lost. Pluged my switch back in and told me that all I needed to do now was to reinstall the switch. I pulled the lever out and darn enough they work.

I told him it must be nice working as a mechanic and having the knowledge.

Get this; He said buddy, I dont work there, I was just droping my car off to have it worked on when you came to me.