Not sure I understand. The flap is a metal plate covered with dense foam rubber. It's physically heavy. Does it sag down or not with power off?
The motor should need a polarity change to drive it to the recirc position (down). I just checked on my car and when I leave the system in recirc and turn off the ignition, the flap remains in the up position. I didn't want to push on it in case I damage the gearing. I noticed that my flap will only operate with the engine running.
When there is no power to the flap motor (ignition off), it stays where it is. It cannot be rotated back because, in its transmission, it uses a worm gear which cannot be rotated by turning the output (flap) shaft in any direction. When deenergised, the motor will not go into reverse polarity run, just sit where it is. The AC ECU will operate the motor in one or the other rotational direction (to close or open the flap) according to whether "Recir" or "Fresh air in" is selected.
Eureka.......I get it. I did not realize that polarity is reversed. When the flap motor is removed, my flap moves with little effort and does not feel heavy. 2.7 v. 5.2? Yes, that explains everything. Thank you. My flap and motor are working perfectly eureka
Not sure. The weight of mine certainly explains why the plastic bosses and the actuators break on these cars. Doesn't the 348 even have this issue? By heavy, I mean not something you would expect an actuator with plastic cogs inside to lift. At least the air direction actuator is rotating a balanced cylinder, not a dead weight.
I discovered that the recirc flap in a 348 works purely on time. It literally applies voltage for a set amount of time, then turns it off. I got to use one of my own little gears today, and ordered the brass bit from ricambi. Image Unavailable, Please Login Image Unavailable, Please Login I had to trim mine a little shorter so the big gear end was more flush with the big gear, and the worm end was adjusted so the small washers would continue to act as thrust bearings. Image Unavailable, Please Login
This is very interesting and the first time someone has observed that the power to the recirculation flap motor is cut by the AC ECU after certain period of time. It would be very good if you could record the time from the flap actuation until the power to the motor is cut-off and post it here for record.
Let me see what I can do...it should be pretty easy. meter, leads, phone. push button, watch 2.6mV got to 8.6V or so (car off) and then stop.
Thanks for the test. My stop watch showed that the 9V (+ or -) is applied to the motor for 20 sec. Assuming that it takes about 3 sec. for the flap to be moved, it means the motor remains stalled for about 17 sec. each time the recirc is changed. Even though the motor does not remain stalled all the time, the actuator gears can still be affected as it is not so much the duration of the stall as it is the impact at each stall that can damage them. From what I can see, you performed the test with the motor (and the flap) disconnected. One question here could be whether the AC ECU cuts the power because it is programmed to do so after 20 sec. or whether it cuts the power because there is no load on this circuit. Another test would be interesting after everything has been connected which would also show certain voltage drop at the moment the motor is stalled. One strange thing shown on your mutimeter is that it shows -23.8 volts in between the flap actuations. Is there something wrong with it?
-23.8mV hard to see in the glare, me holding the camera, and using my long, gorilla arms to push the button, and if I switched the leads, it'd be positive 23.8. I was planning on doing another test as soon as the flap is fixed. its interesting, when you turn the ignition on, it applies voltage in the opening direction immediately. I'm curious now. I'll do a test as soon as my part arrives. sjd
Was your HVAC recirc button in the fresh air mode? Was this after a battery reset or just ignition on/off?
only ignition on/off, no battery disconnect. recirc button with light off when the ignition turns on.
You can verify whether the power to the flap actuator is cut-off, when everything is connected, by just watching (or keeping your finger on) the actuator while the recirc switch is being operated. At the stall, the actuator will twist slightly as it is on rubber mounts. When later the power to it is cut-off, it will relax back.
https://youtube.com/shorts/tsylodsIJWU?feature=share here's the new vid. Voltage still on for about 18 seconds.
