The heater does not work. The fan works fine but no heat is coming through. Does anyone have a diagram of where the on/off valves in the heater hoses is located?

check heater conrol valve under hood if in heater position check the vacuum hoses in dash or the switch that changes the door position

there is usually a fuse for this should be in the line up front somewhere as an accessory item and should be at least a 15 amp..you can check the blower separetly and see if it works..ooppss..check the heater hoses for shut off water valves.. there are 2 , one on each hose(usually under the hood) open these up and the heat should transfer..

change the thermostat if that don't work try the heater core

Both heater hoses should be HOT to the touch (coolant return hose should be slightly cooler than the supply hose). Now, first thing to do is to see if you have vacuum at the heater control valve when the lever is in the HOT position. If there is no vacuum, then you have a problem with the heater control panel or vacuum supply.
If you do have vacuum, then it's probably a bad heater control valve. If you supply vacuum from a hand vacuum pump and there is no change in hose temperatures, then the heater control valve is bad. You can take it out and look inside to see if it opens and closes.
If the heater control valve is fine, then you probably have a clogged heater core. The construction of a heater core is such that if it is 95% clogged, water will still pass through the remaining 5% and come out clean.
If everything checks out fine, then you have to look inside the heating vents for an obstruction.Thanks

First check to make sure you have enough coolant in your system. If you so, has your car's engine been running at its normal temperature according to its gauge? If it has, then you most likely have an issue with your heater core valve. If your heater fan turns on, and the engine is warm, but cold air comes out the vents, then you might not be getting any hot coolant to your heater core. There is valve that controls the amount of hot water that flows through your heater core. It is controlled by your heater controls. On other chrysler made vehicles, these are often vacuum controlled valves. You can locate the valve under the hood by following the heater hoses that pass through the firewall (not to be confused with the AC hoses). The heater hoses are low pressure, and will use simple hose clamps. The valve in question is where you will find four of these heater hoses all coming together, along with a small vacuum line. You can check for vacuum to the valve by pulling the line with the car running, and have someone turn the heater from hot to cold and back while you check for suction at the end of the line. If it seems to work, put it back on the valve and see if the valve operates properly. If you have vacuum, and the valve does not operate, then its actuator likely has a bad diaphragm and will need replaced.

Check heater valve selonoid by removing electrical connection and then remove the 2 lower hoses.Then use a garden hose and water in one of the bottom hose connection.If water comes out the other end, it's good. If good flush out heater core.Make sure the engine is cool and not hot before opening up cooling system. Had same problem in 95 xj12 there was air in the heater core.they call it air lock.

Check the vacuum diaphragm in the heater hose. It's a little metal valve with a hose going to it. When the heat is turned on the vacuum line opens the valve letting hot water pass through the heater core.

if both heater hoses going into the fire wall are hot,remove the heater control assembly from dash and make sure cable is connected and do the same under the hood where one heater hose has a valve connected to it,

The heater bypass valve is bad.It's located on the heater hose under the hood near the firewall.It looks like a little 3in.diameter black disc with a vacuum line attatched to it

Hello

I recently had a simular problem...try to follow the heater hoses that come from the engine and go into the firewall to the heater core... one of the 2 hoses connects to a plastic valve right before the firewall. This valve shuts off the flow of hot coolant into the heater core when heat is not needed.. Look carefully at this plastic valve, there is a wire pull cable with a small loop at the end that connects to a lever on the valve. Have a helper work the heat controls and make sure the cable pulls on the lever at the firewall valve...I've seen some cables disconnected. Hope this helps with your diagnosis.