HELP 2006 Caravan heater - clicking/knocking sound

[CaravanSam]

Well its winter in Ohio and of coarse my heater is having issues !!

Can anyone help me figure out what is happening? I will do my best to describe the problem:

2006 Caravan 3.3 V6 - Occaisonally I hear a loud clicking sound coming directly under the rear passenger side vent window. When this happens it seems like the heater won't switch settings from perharps "floor" to "vent" for example. It's like it gets stuck in whatever current position it is in. If I turn the fan blower off/on the clicking sometimes stops and everything seems to work again, until the next time the clicking starts.

Also, I tried to turn the AC on when the "clicking" is happening and it won't turn on.

Upto now, simply turning the fan switch from off to on a couple of times made the clicking go away but now it seems like it is not helping matters anymore.

I read somewhere that the "heat control board" is in the back under the passenger window. Could that be my problem? I took the plastic wall off and can hear the clicking coming from the rear blower.

I really can't afford to take it to the dealer right now.

Can anyone help me?

[RIP]

Is this a random click or a steady click that speeds up and slowes down with fan speed settings?

You have two motors back there. The blower itself and the mode door motor that controls whether you get cooled A/C air or heated air in the cabin. If you're hearing a random click I would be thinking mode door motor. If it varies with fan speed I would think blower motor. As I recall the mode door motor is forward in the HVAC unit and the blower is aft.

When you say the A/C won't turn on are you saying at all front or rear or just in the rear? If it's just in the rear are you saying the blower won't blow or you're getting heat instead of cool.

[CaravanSam]

Hi RIP and thanks for your reply.
The clicking / knocking is really a steady sound. it sounds like someone is knocking on the door to be let in. Sort of like click,click,click, almost like a relay clicking, its rather loud though.
By turning on/off (or even turning it up/down a few speeds) the rear, or sometimes the front, blower motor the sound goes away.
The sound or speed of the clicks don't change with the fan speed.

Regarding the settings not working; when the clicking is happening, I cannot change the mode of the heat. If I'm on defrost for exampe then I'm stuck in that mode until the clicking stops. Then it seems like a vaccuum switch makes and the mode will change to what ever setting the dial is on, like floor for example.

[urclueless]

why can't people spell vacuum?

you have a mode door that isn't moving and the motor is clicking. you need to take the vehicle to a competent mechanic and have it repaired.

if it really bothers you, don't use the rear heater.

[RIP]

Still have that "plastic wall" off? Take a short length of garden hose cupped to you ear and nail down exactly where the noise is coming from. Got a hunch ur is right. The mode door may be motorising or the door itself is stuck. Changed one on a 3rd gen once. Not too bad.

Hey ur. Why can't people use caps on the first word of sentences? Stick that pinky out there and hit the shift key. It won't hurt.

[CaravanSam]

Thanks again for the replies. Actually I put that plastic wall back on, but now that I figured out how to remove it, it shouldn't be that hard to remove again.

Since both of you believe it's the mode door then thats where I will start.

I will look and listen for the "mode door" sticking and the motor not working properly.

Is this a part that I can buy at Autozone or do I need to go to the dealer?

I might not get to it until after Christmas though.

I will post whatever I find.

Thanks again.

[urclueless]

where to get... ever think about just going to various autoparts store online catalog and looking? www.autozone.com www.napaonline.com www.rockauto.com www.advanceautoparts.com etc etc etc?"

[RIP]

The motor I bought from a dealer was around $20 about 10 years ago. Some parts are reasonably priced at dealerships. The one I changed was mounted on the outside of the HVAC unit. A fairly easy change. Troubleshooting and gaining access were the tougher parts of the job. May or may not be the case on your 4th generation 06. You'll have to prove the motor is toast then determine feasability of changing it.