Yeah. If there's no voltage at the light blue wire, trace it to where it terminates. I don't have fords companion book with wiring diagrams in it, but from looking at the hanes it looks like the light blue feeds off of a grey/red wire from the pcm that also supplies vpwr to other sensors. Try probing the grey/red wire at the intake air temp sensor and checking for voltage there. There should be at least around 11 volts. If there is voltage there, then you've narrowed it down to that blue wire.
Edit:
Sorry it should be 5 volts signal ref from pcm at the iat, not around 11.
It looks like the signal ref is stepped up to the cmp so that explains looking for 10.5 at LT blue. I hate haynes manuals. I want to go check mine for how its wired but dw has it at work.
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The more I'm thinking the less sense everythings making especially without it in front of me.
But if you have less than five volts on lt blue definately trace that one back to where it terminates
Edit:
Sorry it should be 5 volts signal ref from pcm at the iat, not around 11.
It looks like the signal ref is stepped up to the cmp so that explains looking for 10.5 at LT blue. I hate haynes manuals. I want to go check mine for how its wired but dw has it at work.
1 more edit
The more I'm thinking the less sense everythings making especially without it in front of me.
But if you have less than five volts on lt blue definately trace that one back to where it terminates
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