There are two hoses that come from the thermostat at the top end of the engine at the front of the car. These two hoses go back to the firewall. Just above where they enter into the firewall there is a vacuum switch. It has two small hoses feeding it. One of the hoses gets its vacuum from the intake manifold and the other gets eventually fed to the heat control valve.
The heat control valve is located on the opposite side of the firewall. You will notice that when the engine warms up the top hose is much hotter than the bottom hose. Upon start up the bottom hose might be moderately warm because a small amount of warm coolant will flow through it. After the engine is warm this coolant flow will stop because the heat control valve is closed even though you have the heat at maximum. Simply unplugging the electrical connection to the vacuum switch will open the heat control valve and you should have heat inside your vehicle again.
You can also bypass the vacuum switch by unplugging both vacuum hoses and getting a piece of hose to connect them together. This will give you more heat. Ultimately the vacuum switch needs replacing. Also note that flushing your radiator core is easy to do. You should be able to connect a garden hose to the top hose and flush out the core. The heat control valve does not prevent this when the engine is off. Ultimately, you are asking this question because when you turn on the heat in your Jeep it blows cold air. You might find the heat control valve but realize that it really isn't the problem. It is the vacuum line controlling this valve that is the problem and the vacuum switch connected to it.
The grand cherokees never had the water valve.
It is a strange looking part under the hood tapped into the heater hoses on the left side of the valve cover(when standing by the grille). Between the oil filter and the firewall. It has a vacuum hose coming out of the top of it that goes through the firewall to control the different controls of your heater (eg. vent, heat, defrost)
You can obtain a 2000 Jeep Cherokee heater control valve diagram from most Jeep or Chrysler dealerships. The heater control fell diagram can also be found at most auto-parts stores.
Hope this helps and is not to late.
There is no such part on a 1999 Jeep.
No, it is not required. You can remove it and splice the heater hoses together.
In line on the heater hoses on the passenger side of the engine. Has a small vacuum line to it and both heater hoses go through it. The heater hoses are smaller than the radiator hoses and go through the firwall.
jack the front end up and support it then remove one of the heater hoses
with any no heat complaint the first thing to check is going to be the coolant level. then make sure the vehicle is reaching proper operating temperature and that the thermostat is not stuck open or anything. from there check and see if both of the heater hoses are getting hot, those are the coolant hoses going into the firewall towards the passenger side of the vehicle. if one is hot and the other is cold that means you have a restricted heater core. you can try to backflush the heater core by taking a garden hose and connecting through the outlet side of the heater core and spraying out the inlet side. if that does not work you will have to replace the heater core. hope that helps.
heater hoses might have been disconected
No, it is not required. You can remove it and splice the heater hoses together.
In line on the heater hoses on the passenger side of the engine. Has a small vacuum line to it and both heater hoses go through it. The heater hoses are smaller than the radiator hoses and go through the firwall.
On a 4.0L, yes one of the heater hoses does.
near the fire wall where the heater hoses enter
the heater core, heater core hoses or heater control valve is leaking
1. Is coolant flowing through the heater hoses and heater core? Once the care is fully warmed up, running, and the heater on, the hoses going to and from the heater core should be hot to the touch. If not, coolant may not be flowing. 2. Is the heater door, under where people's feet are, broken? This URL may help explain http://www.heatertreater.net/jeep Cherokee 97-04.html
They are entirely different systems. One does not control the other. You have a problem in your heater core, heater control, water circulation or hoses.
jack the front end up and support it then remove one of the heater hoses
rad hoses route coolant to the engine to maintain operating temperature (to keep engine from overheating). Heater hoses supply the heater core (inside most vehicles) with hot water, when heater/ac temperature control knob is turned toward hot, to heat the interior of the vehicle by opening and closing a water flow control valve allowing water to enter the heater core for heat. =;)
The thermostat on a straight 6, 4 litter Jeep Cherokee is located on the very front of the engine. Just follow the valve cover to the front of the engine and you will see the thermostat housing it has two heater hoses coming out of it (one to the radiator and one to the heater core). Simply take out the bolts holding the housing on and remove the heater hoses and the thermostat will pry right out.
If you are looking for a valve in the heater hoses that restricts coolant flow, it does not have one.
you need to replace your heater core take the heater hoses off and lope them with a piece of tubing and drive you will see what i mean