Not sure about yours, but that's not where mine was leaking from. Take out either kick panel, and look straight up (like above where the ECU is/would be). The seam there (it's at the bottom of the whole cabin air intake cowl is) is what started leaking on mine. I couldnt really get to it from above so I snaked my arm up there with some silicone on my finger and smeared it on the join. Dry so far *fingers crossed*

My Truck: 1987 XtraCab DLX 22R 4WD 5 Speed Manual
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"Speed has never killed anyone. Suddenly becoming stationary, that's what gets you." -Jeremy Clarkson