There is no transmission vacuum hose. That is a vent hose.
There are many vacuum hoses, consult a repair manual.
I'd suggest buying a repair manual.
I would start by purchasing a repair manual.
The transmission is controled by the computer. If it will not shift, there is a problem. There is no (vacuum) modulator. Take the car to a dealer or a good transmission shop. Be prepared to have it rebuilt or replaced.
The Vacuum line usually connects to the brake booster , or atleast it does in my Ford explorer
It doesn't have one. Transmissions have not had vacumm modulators for some time ever since the introduction of the AODE models in the late 80's. All transmissions are now controled by the computer. If you think the transmission is having a problem, it should be properly diagnosed at a qualified garage.
It hooks to a vacuum port on the intake manifold behind the carb.
In a Chevrolet Silverado, the vacuum lines that connect to the transmission modulator are typically located on the engine side, near the intake manifold. One line runs from the intake manifold to the modulator on the transmission, while another may connect to the vacuum source, helping to regulate transmission shifting. It's important to ensure these lines are free of leaks for proper transmission function. For specific routing, consulting a service manual for your model year is recommended.
Trouble code P1490 means: EVAP System Vacuum Cut Bypass Solenoid Circuit Malfunction
Pull off the vacuum hose. If there is any gas present in the hose, it's faulty.
You can get that at the library in one of the Automotive Repair Books dealing with Mercury Villagers. I think you mean Vacuum Hose Diagram anyways.
Trouble code P1490 means: EVAP System Vacuum Cut Bypass Solenoid Circuit Malfunction