The jiggle valve's a small hole on the thermostat itself (not a separate part). It's merely there to help free the system of trapped air. Follow the hose from the top of the radiator to the motor and you should find the thermostat housing. Removing the housing will reveal the thermostat and at the top of the Tstat should be a small hole -- that would be the jiggle valve (if your thermostat actually has one).
No.
A 1993 Jeep does not have a transmission modulator valve.
No
A 1999 Jeep transmission does not have a modulator valve.
Jeep transmissions do not have modulator valves
A 1997 Jeep 4.0L does not have a pcv valve. It uses an orifice in the top of the valve cover.
It is the Positive Crankcase Ventilation (PCV) valve.
The 2002 Grand Vitara EGR valve is located on top of the engine. The EGR valve will be between the engine and the battery.
Wrench tight
The PCV valve on the 1995 Jeep Grand Cherokee Laredo V6 engine is on the oil filler tube. It is on the top of the engine.
The Jeep 4.0 did not use a PCV valve. However, there is a fitting on the top of the valve cover at the very back of the engine that serves instead of a PCV valve.
Doesn't have one.