[jtmarten]

Originally Posted by 777stickman

I think what your talking about is called the heater control valve. The rubber vacuum line runs up to a hard plastic line towards the rear of the motor. That line then runs over the top rear and to the drivers side for the vacuum source.

This is on my '98 Sub 7.4.

Thanks, I'll check it out tonight. Wasn't sure if it could be a possible source of my current problem.