Electrical Light issues

wmburns said:

First check for always on power at fuse F2.19 and F1.10. Confirm power in and out (both sides of the fuse). Likely fuse F1.10 is good since the head lights work but best to check to be through. If possible use a test light that will "load" the circuit.

Now at the head light switch, confirm there is +12 volts at the R1 (wire color BN) with the switch in the "park" position.

IF there's no power at the BN wire, I would inspect the head light switch connector for signs of heat damage. Why? Because frequently when the head light switch fails by over heating the heat is also transmitted to the connector. This heat will distort the plastic as well as loosen the metal terminals making for a poor electrical connection.

1999-2004 MY fuse panel schedule:

1999 Mustang GT with 2001 motor swap, wont fire. Please help

First off thank you for taking the time to read this, I hope that you will be able to help me out in some way to get a 4 month project off the ground and back onto the streets. I'm not a master mechanic but know just a little bit, enough to do your typical maintenance, overhauls, and swaps. I...

www.allfordmustangs.com

IMO the reason WHY you are seeing the "strange issue" between settings is because you are forcing the switch to be between settings and this is allowing the headlight portion of the switch to "back feed" the parking lights. This is not the usual setting for the parking light switch but it's normal (I have created the same situation myself).

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