Where is the modulator valve on a 1994 1500 Chevy pickup?

The modulator valve on a 1994 Chevy 1500 pickup is part of the transmission. It's not a standalone easily-accessible component like a fuel injector. You won't find it externally on the engine or transmission case.

To find it, you'll need to access the transmission itself. It's *inside* the transmission case, typically located near the governor and connected to the valve body. You'll have to remove the transmission pan and valve body to access and replace it. This is a significant job requiring transmission expertise and special tools.