Headlight, Running light issue
Senior User
Joined: Jun 2013
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https://troubleshootmyvehicle.com/fo...light-switch-1
Scope Wizard
Joined: May 2019
Posts: 6,530
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do a Continuity test on the switch to be sure it matches the functions of the Schematic ...Find out why you do not have power on the Tan/Wht wire ... it seems that you said you have power on Fuse #4 so is the wire burned open ???
IF you do not understand the schematic we can help with that too.
Scope Wizard
Joined: May 2019
Posts: 6,530
Likes: 25
OK from the schematic you can call pin 'B' "B1" and call 'A' "B2" ... then you can use this guide https://troubleshootmyvehicle.com/fo...light-switch-1
Scope Wizard
Joined: May 2019
Posts: 6,530
Likes: 25
I suspect there is a bad connection on the fuse #4 circuit (tan/white) as mentioned earlier by Lone Wolf. Inspect the terminals in the fuse box for loose contact or corrosion. Wires on the back side of the fuse box can break, but it is rare. Click on the link for testing the light circuits and switch. The headlight circuit for your truck is basically the same.
https://troubleshootmyvehicle.com/fo...light-switch-1
https://troubleshootmyvehicle.com/fo...light-switch-1
I guess I missed your comment
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Scope Wizard
Joined: May 2019
Posts: 6,530
Likes: 25
it should be hot at all times, IF not then the Park Lights will never come on.
IF fuse #4 has power on both sides of the Fuse then trace that wire to see where it is OPEN.
As mentioned it could be on the back of the fuse box where it connects to the fuse. or it could be a bad Splice.
Senior User
Joined: Jun 2013
Posts: 170
Likes: 4
If you find the fuse box or wiring to it is the problem, it may be more practical to bypass the fuse box. Install an inline fuse and additional length of wire from Batt+ to the tan/white wire near the headlight switch. Batt+>inline fuse>headlight switch.
I had to do a similar bypass for the blower motor circuit in my truck. The amp draw from the motor caused the fuse and terminals to melt. New inline fuse and blower motor fixed it.
Scope Wizard
Joined: May 2019
Posts: 6,530
Likes: 25
IF you have to add a new wire the easiest thing to do is just place a 15 AMP fuse between the Blk/Orn wire and the Tan/Wht wire, you can do this when splicing in the pigtail
See the Schematic I posted it will be between pin 'B' and 'A'
See the Schematic I posted it will be between pin 'B' and 'A'
Posting Guru
Joined: May 2015
Posts: 2,036
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I had to do something similar for my running light power. So far no issues
Senior User
Joined: Jun 2013
Posts: 170
Likes: 4
Good to hear you got it fixed
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