Check to see if these wires have 12 volts at the mass air flow sensor using a multimeter. This voltage will only be applied for approximately 5 to 30 seconds after the engine has been shut off ...

He decided to replace this with a modern mass air flow (MAF) sensor instead, and documented the process online.

The air flow sensor is located directly in the intake air stream, between the air cleaner and throttle body where it can measure incoming air. (hot wire automotive mass air flow sensor) Primary ...

This sensor type is based on the principle that if a mass is maintained at a constant temperature (above ambient air temp), the thermal loss is proportional to the flow of air over that mass.

GM has issued a recall for certain units of the Chevy Low Cab Forward 3500 and 4500 models due to an issue with the mass air flow (MAF) sensor.