Have a 00 Grand Caravan with single zone heat/air. AC blows cold and heat is hot, all modes work, and just replaced dying blower motor. Problem is the system started getting stuck in heat/cool and you'd have to tap on the blend door actuator to get it to switch over as you moved the slider. I Also at first could get the system to pass all calibration and cool down tests as long as I tapped on the old actuator. Bought a new doorman actuator and I absolutely cannot get the system to calibrate for the life of me!!! I have searched everywhere and have a dealer repair manual. I've even tried calibrating it in a heated garage as I've seen some posts that it has to be above fifty degrees or some such nonsense (I did get it to pass calibration once in garage but actuator still wouldn't move).

The wife and I have resorted to reaching up and manually switching it from cold to hot (as it will swing back to cold when blower stops...real pain during winter). I also realized while changing the blower that this stupid vehicle apparently only powers the recirc door when the blower is spinning...meaning going down the highway there is ALWAYS air blowing and you're either freezing cold or burning hot.

It is also maddening that until you pass the calibration test the vehicle will not give you error codes, so i have no way to actually troubleshoot the system. I Don't recall ever having codes blinking when I turn the ignition on (started this project months ago).

In my last vain attempt I started thinking about the fact that I don't get any error codes and when I plug in actuator and calibrate it will turn from any position I put it in (pry cover off and manually turn gears) to straight up and down in the cold position 12 o'clock. I took front bezel off and cleaned the slider bar with alcohol, it was pretty nasty and had plastic peeled off the sides (I'm guessing a dust shield that wore down), the actuator responded a few degrees at first then stopped when I tried to calibrate. I'm wondering if I should manually move the actuator to its furthest heat position (say 4 o'clock) and then try to calibrate so the system picks up the full range of voltage...I can't remember how it came new from factory.

I hate to take this old van to dealer as I live in the stix and already bought part. If I can't figure it out soon I'm going to rig up a manual choke cable to switch it! Any ideas or thoughts would be appreciated, I'm pretty car savvy but this has me at my witts end!

 

No one?

 

Not much to it. A control panel, two wires and an actuator. Try an OEM actuator. If the wires to the actuator have continuity then you may need a new control panel.

 

Make sure the ground wire for your HVAC control panel is snugly connected. I found one that was left loose when someone replaced the factory radio with an aftermarket radio. The blend door would not operate except by hitting the dash and it absolutely would not calibrate (left the lights blinking and they would never stop). Securing the ground fixed the problem after re-calibrating. The only other suggestion I have would be to spray the HVAC connector with contact cleaner and try seating the plugs a couple of times to sweep the contacts clean. Good luck!

 

Hey hoosierrun that's the first good lead I've had! Might also explain why it worked when I tapped on it...dunno. The cigarette lighter plug is **** and pulls out; I wonder if that didn't stress the wiring harness somewhere. Dang I really don't want to take the whole dash apart...

I had HVAC controller apart once but only saw two large plugs. Is there a separate ground wire somewhere? I'll take another look this weekend, its actually warming up a bit and got a 3-day weekend! Saw on ebay they have the correct one for like $35 as well so might try that route too eventually if I don't salvage a choke cable first. Wife has about had it with this POS, but hey it was free and still gets 23+ mpg!

 

OK thought I should update as I finally got it to calibrate! First off it was about 55 degrees today, I don't believe that was the deciding factor but can't say for sure.

From what I can tell when you hook up an actuator that the computer doesn't recognize you have one chance to calibrate it. Let me explain... If the angle sensor reports a different position than it was in when you shut off the ignition then it will spin counter clockwise to the cold side if you move the slider, and it will spin too far as its not calibrated. After this initial movement the actuator will not calibrate as any further movement could apparently damage the damper door.

So...near as I can tell the slider has to be on cold when you turn the ignition on for the first time on a 'new' uncalibrated actuator. What I did was to carefully pry the cover off, remove the motor, spin the actuator to the midpoint between hot/cold, and reassemble. I should add that these actuators are Chinese junk and I think part of my problem was the motor wasn't keeping constant contact; so bend all the contacts out. It helps to turn the blower fan on and manually spin the damper door clockwise till it falls to full heat then you can put the actuator in its key position and install screws (or hold it in place while you calibrate). During calibration the actuator will go to full cold then full hot and back to cold and hopefully no lights will be blinking. Dunno why I lost calibration on the old actuator but I'm guessing the contacts bent and motor would only turn as I tapped it.

Hope this one day helps someone else. Let me know if I can clarify anything!

 

Glad to hear you finally got it!