Tested the Red w/ Yellow wire right behind the plug...Turned the key on, switch in autolight position (verified autolights were working because parking lights were on), and the best I got was +0.08 VDC

 

There is your answer.

The Red w/ Yellow stripe wire is broken somewhere between the BSM/VSM and behind the headlamp switch.

Time to physically trace the wire back to the half way point ( BSM to headlamp switch ), and try the test again.

I post physically trace the wire back, to make sure you are testing the correct wire.
Just because you found a Red w/ Yellow stripe wire in the door sill, does not mean it is the auto lamp circuit, it could be something else.

At the half way point, try the test again.
If you get + VDC, move to the half way point from that test point to the headlamp switch and test again.
If you do not get +VDC, move to the half way point from the test point to the BSM and test again.

This is dividing the circuit in half diagnoses process. It is time consuming to physically trace the wire and retest, but this is why shops get the money they do to diagnose electrical problem.
- Also a good reason to get one of those piercing meter probes, it will make things go a lot faster and easier to tape up the test point.

 

I'm assuming the half-way point in the circuit is the blue dot 'S267' right?




Do you know where the half-way point is? I found this 'intersection' below the driver side carpet. I'll appreciate it if you point me in the right direction.

 

No, splice S267 is up behind the dash, close to the headlamp switch.

Looking at the side of a SuperCrew, half way between the BSM on the back wall of the cab, and the main headlamp switch in the dash; I would say is the B pillar.

That is a little inconvenient to pull all the plastic, so I would choose just inside the rear passenger door by the B pillar.
- This also makes it easier when starting to physically trace the wire. Do not guess at which Red w/ Yellow Stripe wire it is; physically trace the wire

 

Quote:

Originally Posted by SSCULLY

No, splice S267 is up behind the dash, close to the headlamp switch.

The problem was in the S267 splice...








Red w/ Yellow stripe wire coming from the BSM...

 

Woohooo!

 

I'm having a similar issue, can someone tell me where the BSM is on a regular cab? Is it behind the vinyl wall behind the driver's seat?