Where is the heater water control valve on a 94 Grand Cherokee Limited? One heater hose goes from the water pump to the firewall, the other from the thermostat housing to the firewall. There is no valve on either hose in the engine compartment. The valve (wherever it is) is open regardless of the position of the heater control knobs.

The hose from the water pump should be connected to the heater control valve. The other hose goes to the return from the heater core.

Let's try to pinpoint the trouble.
First, check the coolant in the radiator, and if it is low, you need to fill it and run the engine with the heater on for about 5 minutes to get the air out of the system.
If you still have no heat, warm up the engine some more by driving it or idling it for about 10 minutes with the heater turned on full blast.
Now, shut the motor off and open the hood.
GENTLY feel the radiator, it should be hot.
Now feel the top and bottom radiator hoses, they should be hot.
Next, feel the heater hoses, they should be hot also.
If you need to, have someone point out these parts to you.
If the heater hoses are not both hot, perhaps the heater hot water valve is closed, and it may be stuck closed, or the control wire or vacuum hose to it may be "broken".
The heater hot water control valve is near the firewall, at the back of the engine.
How you can tell it is by " it has a heater hose in the front and one in the back".
The one in the back goes to the heater, the one in the front goes too the engine.
If the radiator hoses are not hot, you may have either a stuck thermostat (in the open position) or you may have no thermostat at all where there should be one.
Be blessed.

98 grand cherokee limited 5.2L same problem found leak not from heater box but from drain mount on firewall under the glove box not behind it. drain line should be located behind right front tire in the frame. Turn your wheels hard left look inside fender well right side towards back side. hole in frame where drain line should come out.

Get jeep up to operating temp
Turn on heater to max heat
Hood feel 2 heater core hoses goint into upper passenger side of engine compartment firewall.
They should feel too hot to hold
If it's not hot, could be 6 things
1. heater control valve is bad
2. Vacuum to heater control valve is bad
3. clogged heater core.
4. Bad thermostat
5. Bad waterpump
6. Needs more coolant (check when system is cold)

Do these things:

1. Disconnect vacuum line from control valve and feel under valve to manually move valve to open position. This should let hot water flow through core. If you now have heat inside, replace the heater control valve. Or you can disconnect the plunger on the heater control that is hooked on to the silver bar on the bottom of it. With it disconnected you can manually move it to the open position. It will always remain on.

2. When system is cold, disconnect both heater hoses going to heater core. hook up a water hose to one side of heater core and flush out any gunk. When you get done, the water should run clear. If you see lots of gunk come out, that was probably the problem. Replacement is like $20-30

3. When system is hot and engine running, squeeze the upper radiator hose (using gloves) when you release it you should feel a surge of water. Proves your water pump is working. If no surge, check thermostat. If thermostat checks good, look at the weep holes at the bottom of the water pump for traces of antifreeze. If you see a trace or stream of coolant, indicates bad pump.

4. As far as testing the thermostat, watch as your engine heats up on the gauge. when it gets to a certain point you will see the temperature rise, then lower, then rise again. This means your thermostat opened properly, cooling the system temporarily, then heated it back up. Replacement is around $5

Try these and see how it goes.

The lower radiator hose goes to the water pump, will have to drain radiator to replace it. You should hae 2 heater hoses, if your engine is an inline 6 cylinder one hose will go from the frot of engine by thermostate housing to the firewall and the second hose from the back of engine to firewall

I don't know on the Grand, but our Cherokee has a water valve right by
the firewall on the heater hose to control the heat. Not actually a fuse as it is heated by the coolant running from the engine, but apparently there was an issue with some s*&t heating systems. What is the actual problem you are having? as this 'fuse' may actually not exist.You may need to simply flush your radiator, replace the coolant after checking near the firewall for the valve that lets the hot water flow through, This may be the problem?

your control valve is in the dash assembly, passenger side. buried. its not in the engine compartment. im having the same problem with mine...i am thinking its more like the climate control is screwed up.

Go to engine compartment, locate heater control valve. It will have the heater hoses connected to it that pass into the firewall. Unhook actuation plunger on the control valve. This will allow the coolant to flow though the heater core at all times. Now you have heat. If you get too hot, you can control it by the hot/cold settings to adjust the heater door.

there is a bracket attached to the pipe just above the water pump bolts (this bolt looks similar to the water pump bolts). there is also a bracket attached to a long, thin bolt just under the valve covers on the drivers side. you'll need a long socket to get to this one. once those two brackets are freed up, you should be able to work the heater hose out of the hole in the water pump. of course, that metal pipe attaches to a rubber hose about halfway back from the water pump to the firewall, so you'll want to undo the hose clamp that holds it in place and slide the metal pipe out of the rubber hose.

i'm not sure what you have in mind, but this should let you accomplish it. note that there is an o-ring that fits on the water pump end of that metal pipe. it's included when you buy the water pump.

have fun and be careful.

1. Remove negative battery cable
2. Open radiator valve - drain cooling system
3. Remove cooling fan and shroud
4. Remove belt
5. Remove water pump pulley from hub
6. Remove hoses from water pump
7. Loosen heater hose coolant return tube mounting bolt and nut.
8. Remove the tube. Lose the O-Ring.
9. Remove water pump mounting bolts
10. Loosen the clamp on the bypass hose.
11. Remove the hose as you pull the pump away from the engine.

Hope this helps

Mike