2000 Base Caravan 3.0L V6 - as of 2021 late winter, the heater stopped working. I also noticed that, when I shift from coolest to warmest temperature, the air flow slows to almost off. Bizarre?
A/C works fine and, after replacing the water pump (and timing belt at the same time), it is no longer leaking coolant.
Recently, went over 145K mi.
Am seeking WOTL.
I have no idea what WOTL means.
Wisdom Of The List
There may be a problem with the AC/heater control module or the BCM.
Here’s a diagram of the HVAC circuit.
Tester
Also check for a plugged heater core. Both hoses to the core should be hot. This wouldn’t explain the decreased air flow, though.
My knee-jerk reaction to the lack of heat was a problem with the heater core but, as NYBo says, it wouldn’t explain the reduced air flow.
The schematic looks daunting. I’m wondering how to test.
Oh, one more Bizzaro thing. Fan setting 4 (next to 5, most airflow) is OFF. Really OFF, as the recirc & A/C lights will go out if I set the Fan Speed to 4. I wonder if the two are connected somehow.
Also - what is the BCM?
Body Control Module.
Tester
The things that come to mind is a bad resistor or a dirty cabin filter or both. When on heat, is the air warm with little airflow or is it cold?
It’s cold as well.
This points to resistor or climate control module.
Maybe dirty cabin filter, unless it’s normal with A.C. These models are prone to have climate control calibration issues. They are supposed to self calibrate at a set schedule, but sometimes I have to force a calibration. This may be why you have no heat. The mode door may be always in the cold position. I’ve sometimes had luck by just turning it from all the way hot to all the way cold 3 or 4 times. If that don’t work, Google climate control calibration for a 2000 Caravan and do the calibration.
Cabin filter? Is there one on the Caravan? I’ll check the Owner’s Manual.
I’ve tried the percussion method, i.e., sliding it from cold to hot, back n forth a bunch a times, but no difference. Since the airflow changes somewhat gradually, I am guessing that this is an electronic slider and not a cable.
Are there any fuses for the heat(er)? Again, I’ll look in the OM for something like that.
And I’ll get back after I find/try the calibration steps.
TY to all.
The cabin filter is accessible inside the van just above passengers ankles.
I found several YouTube videos on calibrating it and… apparently it is not calibrating successfully. It ends with the Recirc and AC lights flashing.
I tried both button combos: (a) Rear Wiper & Wash, (b) Wash & AC. Both end with the Recirc/AC lights flashing.
One video showed the fan off, another on high. I tried (a & b, above) but got the same results either way with the fan.
Fan speed on 4 (of 5) is still OFF. When Temp switched to hottest, the air output is minimal, though I can still hear the fan.
One video showed the text for running this calibration but not the complete text, only a bit. I’d love to see more of that. Maybe the Recirc/AC blinking is a code?
BTW, turning the key to off stops the blinking and they don’t blink again unless I run the test/calibration.
Blinking after the test means there’s a fault in the system. To do the tests you turn the key on, press the two designated buttons at the same time ( I don’t recall which ones they are but you know because you’ve gotten it into the test mode). Then you wait the 20 seconds or 2 minutes depending on the system. If anything continues to blink after that there are faults. Depending on the fault type, the lights will stop blinking when you cycle the key, but sometimes the blinking is permanent until the repair is made. Right now I don’t recall if the blinks represent a specific code.
I just looked in the service manual. It says if the lights continued to flash there is a fault code stored. It does not say that the blinking patterns identify a specific code. So you probably have to get the codes read from a scanner that has the ability to communicate with the climate control module.
A side note: no heat can many times indicate that the engine is low on coolant. If this is the case your engine will overheat. The temperature gage in the dash on these vehicles are pretty squirrelly. If the temp gage ever gets to the red it is severely overheated. If it reads hotter than it normally does it means your overheated.
I did have a coolant leak earlier in the year but had the water pump replaced (timing belt at the same time, it was due) and the coolant has not leaked since. The reservoir is near the max line.
The heat was working fine thru the leak but then, before the water pump was replaced, stopped working. Can low coolant cause the heater core or the control panel to go south?
So it’s some special code reader? I’ll call my regular guy before I go the route of the dealer.
Will post back tomorrow.
Coolant goes through the heater core to heat the van. If you are low on coolant or coolant doesn’t get to heater core then you have no heat. But you will have an overheated engine. It has no bearing on the control panel or heater fan. Have your guy check to be sure it’s not overheating. You seem to have 2 different issues going on.
Something in the cooling system has to control the coolant pressure. If that’s done w/a pressure cap on the radiator, it is possible the radiator is low even though the reservoir shows full. If so, remove the radiator cap and inspect the coolant level in the radiator. I’m thinking however the problem is either an electronics failure – as mentioned above – or the heater core (the part that produces the heat inside the passenger compartment) is plugged up and partially blocking coolant flow. It’s conceivable the electronics would detect that b/c the heat inside the heater core wouldn’t dissipate as quickly as it should. If you feel lucky you could just try replacing the radiator cap, doubtful, but might work.
