No, it is not overheating and the coolant level is at the neck of the radiator. The coolant in the reservoir does go up and down a bit, not enough to top it up, though. It has been fine since the water pump was replaced back in the Spring.
If I wasn’t clear, the heat stopped working BEFORE I replaced the water pump. And, SINCE the water pump was replaced, it no longer leaks coolant and the engine no longer overheats.
The cap was replaced a couple of years ago, BTW, but swapping out the cap did not solve the problems at that time. Since the reservoir level does vary, it seems to me that the cap is doing its job.
Where would a diagnostic reader connect to the Caravan to get the error code(s) for the HVAC control system? Same as emissions, etc?
Yes, you don’t need a designated scanner just for the climate control. You need to use a scanner that is equipped to read the climate control module. For example: you can purchase a cheap scanner to read codes but it will not read codes for the ABS module. For a little more money you can buy one that reads codes including the ABS module. You need to use a scanner that is capable of communicating with the climate control module.
Have you tried
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air bleeding the coolant system using the manufacturer’s specified procedure?
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back-flushing the heater core?
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inspected the blend doors for proper function?
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measured the temperature of the incoming and outgoing heater core coolant hoses?
Beyond that, as posted above, it may be necessary to read the hvac system codes; if so, that would be the time to stop the diy’er approach, and get some professional mechanic help, a shop that has the full set of chrysler/dodge electronics diagnostic tools.
The symptoms seem odd in their entirety. If I was only not getting warm air, that would be one thing, but it’s not.
The Reset operation ends with the Recirc & AC LEDs flashing. That’s not what’s supposed to happen, right?
Correct. After reset if there are no faults the lights will turn off after 2 minutes or 20 seconds depending on the system. If they continue to blink there is a fault and fault code(s) stored.
That indicates the “cool-down test” has failed. The evaporator must be warm when beginning the calibration procedure. If the evaporator is cold at the beginning of the calibration, the computer will not see a change in temperature and the test will fail.
To perform only the cool-down test; switch the ignition on, do not start the engine, switch on the blower motor for 30 seconds to warm the evaporator to ambient temperature. Start the engine, press and hold the rear wash and A/C buttons for 5 seconds. If your air conditioning does not work this test will not pass.
I purchased a used replacement control panel and, after replacing, there was absolutely no change in behavior. I think the odds are slim that, even though it was used, the 2nd contol panel would be defective in the same ways as my panel.
So, perhaps the fan speed has to do with a relay? The change in air speed (when changing from cold to hot, not changing the fan setting), I have no idea, perhaps a blend door actuator? And the lack of heat, problem with the heater core.
My next step would be flushing the heater core. Thoughts?
When my Chrysler minivans stumped me, I often found help at allpar.com - they are devoted to Chrysler vehicles and have a minivan forum. Good luck.
First, listen to your fan at off. Then turn it to low. Does it speed up? Does it speed up again on the next speed? It should speed up after each time you turn it up. Do not compare air flow but go by listening to the fan motor. If the sound of the fan motors speed increases with each position and then turns completely off for speed number 4 then you most likely have a bad resistor.
Then for problem#2:
If they both get hot which I suspect they will, you have to address the faults in the system. You obviously don’t have the resources to check the codes.
With the fan on high, put it on defrost. Then set it to floor heat, then vents. Does the air flow where it’s supposed to? If yes, then your mode door actuator is working if no, then the mode door is sticking or the actuator is bad. Then with engine warmed up direct the air through the vents. Turn A.C. on. Put it to cold. If it’s cold, turn it to hot. If the temperature doesn’t change, you probably have a sticking blend door or blend door actuator.