Help with actuator control

Other Hardware Motors, Mechanics, Power and CNC
1

Hi, I'm new to the forum and have a difficult problem to solve. I'm retired and it's been awhile since I have played with my Arduino projects. But, because of them and the hours I enjoyed learning I figured this is the place to get some help. A couple of decades ago, I had your help figuring out some difficult issues and I'm knee deep on this one.

I have the entire dash out of my car chasing an electronic gremlin. I'm dealing with all kinds of misinformation and I'm stuck. I can supply pics of service info, the circuit board and parts etc.

What I need to do is figure out how to operate a HVAC actuator. The service manual has some typos and some really unclear info so it is not helping. No info out on the web either. I have attached pics of the service manual which deals with testing the actuator, the module/programmer and shorts/grounds. I have 3 actuators out of the vehicle and have run all the tests several times in car. DTC's are inconsistent and I have swapped a programmer and replaced 1 actuator that was easy to get at. If I can figure out how to run the actuator it will make a difference whether to keep going forward or junk the vehicle. So, I know I'm a bit off hobby electronics and and it's not Arduino related but I'm just stuck. Any info would be helpful and I know one of you is saying to him or herself....oh yea, piece of cake....I hope anyway.

Another way to view the originals-
https://drive.google.com/drive/folders/1AGmrUt80JSax1uocmME_3zoQzZxjN-4b?usp=sharing

20230512_170953
20230512_1709531800×4000 525 KB

20230512_171052
20230512_1710521800×4000 557 KB

2

How were they operated originally? Something basic is missing to me.

3

From the dash controller, it's an automatic system, set it and forget it. Push a button for AC, heat, fan, blower, etc. The dash control sends signal to program module which reads all the hvac sensors and sends the appropriate signal to the appropriate actuator to control vents and hot/cold air flow.

4

.... I probably should add that what I'm trying to accomplish is to test the actuators on the bench to make sure that they are bad before I replace them and make sure it's the actuator and not the programmer. Or both or one or the other, see what I mean? It's taken me 3 straight days to disassemble the car to just access the parts. I want to make sure that I have the problem resolved before I reassemble the car.

20230512_133411
20230512_1334111800×4000 596 KB

5

Okey, that's a different matter. Ideally we would like datasheets, technical manuals. Know that every helper is a newbie to Your stuff, but we know how to read manuals, datasheets etc.

What signals are there to the actuators? Can You measure voltage, signals etc going to the actuators? Are several of them not working? How/when did this start?......

6

изображение
изображение1115×877 92.3 KB

изображение
изображение558×558 17.6 KB

1 Like
7

Thats what I came up with, (except Rp1 and the 10k), but i did not get any response. What's RP1? Switch? No.
As I understand what you are saying is- contact 6 to RP1 creates ground, the other way for 5v. What do i connect the analog0-5v to, a potentiometer? This brings up the issue with ground also. Pin 7 on 3 different acuators does not share a ground in the actuator with the motor ground so actuator circuit must be grounded through the prog module and seperate from the motor, yikes. I could get the motor to run in one direction and stop, but not reverse. No response to ground. So, makes me think the ground was an issue but the resistor you show, does that take pin 6 to 0v's? Are you telling it to sense......I need just a bit more info because I am confused. I got siezed up on the service manual description and finally decided the circuit should work without sensing feedback but im probably wrong on that? Your circuit is doing that i think?

8

RP1 is a potentiometer, any resistance from 1k to 100k, it can't be simulated by arduino itself, but arduino can measure voltage on sense pin, so then it know the state of motor and will stop rotating(somehow).

9

So I can connect a 1.5v bat or 5v regulated to the analog side and turn the pot to make it function? All grounds shared, correct?

I dont think i remember enough to hook it up to my arduino board, i might have to relearn so much i have forgot over the years. You are really helping me, thanks!

10

"analog side" is an output. you not forced to use it by test. connect ground, power lines and potentiometer. rotate poti in middle position and give voltage from power source. then rotate poti in one side, you should hearing motor rotating or stall, turn poti to the other side and motor should rotate other direction. set potentiometer in middle position to stop the motor.
if both module works and not going to scrapyard then we can to think how let arduino to manage HVAC control

11

Ok, understood. I will be trying this today. First, I need to make some type of female pin adapter that fits the board pins. :slightly_smiling_face:

12

"analog side" is an output. you not forced to use it by test.

It just hit me, this connection would go to the programmer "sense" pin and would provide the feedback for position. So it sounds like i could power the programmer and the dash control on individual actuator circuits and test them. Is that correct? Oh what fun!!!!!!!

I do realize- first things first, need to accomplish control of the actuator on the bench. :+1:

13

probably the dashboard heat control is a potentiometer.

изображение
изображение529×649 16.8 KB

изображение

14

I have taken it apart to see anything obviously wrong and it looks like the whole thing operates on simple switches, but im not sure and you would know something,
i do not . Note the over heated resistors In the pic. I found a used replacement on ebay and it was in the same condition and it did not fix the problem.

20230502_130416
20230502_1304161800×4000 790 KB

15

Man-O-man, my brain is already overheating and its only 8AM!!!!!!!!!

изображение
изображение529×649 16.8 KB

16 
const byte toInput = 3;
const byte toSense = A0;

void setup() {
  pinMode(toInput, OUTPUT);
  pinMode(toSense, INPUT); //only for semantic
  digitalWrite(toInput, LOW);
}
void loop() {
  while (abs(analogRead(toSense) - 512) > 500);
  digitalWrite(toInput, !analogRead(toInput));
  delay(1000);
}
17

No, not overheated. That is normal for FR4 circuit boards when wire wound resistors are mounted close by. They produce a lot of heat! and that is what they are designed to do. Normally the resistors would be mounted so air could flow around them and remove the heat.

18

Look at that gear, it's cracked and will probably slip when turning and fail to move the shaft.

Captura de pantalla 2023-05-13 113331
Captura de pantalla 2023-05-13 1133311051×735 41.1 KB

Regards

19

And look at the chewed up gear teeth where the crack is. The crack likely occurred at the same time.

20

No, not overheated. That is normal for FR4 circuit boards when wire wound resistors are mounted close by.

That sure seems to be a design issue, that is to hot- in my case, it looks like it melted the boards traces. Maybe not? I believe you and it's new to me so....
It is another part to the "gremlin mystery"- partial board failure do to excessive heat?

To clarify- anything that is hot enough to burn, discolor via heating or alter another material, I am calling excessive or overheated.

I can upload a pic of the traces if you would like.