The human factor in malfunction
After eliminating such a malfunction, which I will discuss below, I sometimes ask the question: “Was it the car owner’s confidence that“ it is so easy to do, ”or self-confidence? Or did the crisis crush you so much that you have to save on traveling to a car service? it was said that if you’re not constantly engaged in the diagnosis and repair of cars, then there’s nothing to experiment – it’ll cost you more. So it happened here, listen to a short history of this simple, in the opinion of the client, repair.
The car entered for repair with a malfunction in the climate control unit – the “heat-cold” position is not regulated. On these machines, step-by-step control of the dampers is already used, unlike previous models, where there were actuators for servos with feedback, that is, there was a potentiometric sensor, which enabled the climate control unit to understand what position the damper is in (“feedback “). In the circuitry of modern cars (Mitsubishi ASX, Mitsubishi Lancer 10, Mitsubishi Outlander) a stepper motor is used: the control unit sets a certain number of steps and everything is regulated relative to this.
In the photo, the climate control actuator taken is responsible for the actuator of the “heat-cold” or “air mix” damper with connected probe probes.
When fixing this malfunction, the logic probe helped me.
In order not to take your attention for a long time, I refer to our articles, where it is written in detail, with pictures and videos: “Devices for car diagnostics” Part 1 and Part 2
With the help of a logical probe, where it is possible to simultaneously trace the presence of signals on four channels, I start checking while checking the circuit: “this is a commonplace stepper motor”:
What it turns out: three channels are now turned off, and the fourth “sits on the minus” (green LED):
The position of the regulator was “maximum cold”. Now check in a different position: “Maximum heat.” What we see:
The signal passes, but the channel on the right as it was shorted remains the same (the green LED is on). This may indicate that the control of this actuator climate control does not work. If the green LED is on, it means that there is a constant “minus” there. Or in another way: “The control transistor of this channel is broken to ground and constantly open. Accordingly, the winding of the stepper motor will constantly heat up, and the actuator may also burn out.
And how it should be: when regulating the temperature, the LEDs from red to orange should alternately blink.
Three channels show this (there the LEDs blink, you can see the video), and the fourth is not. “Sitting on the negative.” It is necessary to check the controller, which is located in the same panel where the control knobs are located:
For clarity, I disconnected the connector from the actuator damper, and the photo shows that the fourth channel continues to “sit on the minus”:
I constantly check the diagram: what color of the wire (black with a blue stripe) and where it goes:
Next, you need to remove the control unit and carefully study it …
What is important here: you need to carefully look at another socket where there is an “emergency gage and airbag”, there the connectors are the same with the climate control control unit (or just the stove, as you like):
If connected incorrectly, we will have a burned out climate control unit. (in the photo above and below: on the left is the panel “emergency lights and airbags”):
As a result, it turned out: as expected, the sources of the malfunction lay again in the “human factor” plane. The owner of the car decided to independently establish climate control. As already mentioned, on these models the external climate control panels do not differ from the air conditioner, they can be replaced (on Mitsubishi ASX, Lancer 10, Mitsubishi Outlander cars).
The owners of the auto air conditioning control unit removed and installed the climate control control unit on their own. And everything would be fine, but the connectors are mixed up. Moreover, the length of the wires allowed (which is a bit surprising, since the Japanese usually always accurately calculate the length of the wires, probably assuming that if they change something so that one connector is not put in place of the other).
Here, the connectors (chips) were mixed up: the connector from the emergency gang was connected to control the air conditioning. And all that was needed was to somehow mark the connectors when removing. We didn’t bother with this, didn’t mark it at all and got what we got – the climate control unit burned out safely (out of order).
When the owners saw this, they put everything back quickly – again it does not work. Alas, in such a case, “died so died!”.
The “human factor” is tenacious, it is not killable, even despite dozens of reminders of what this may lead to. Some of our articles on the subject of “The human factor and automotive wiring”: Part 1, Part 2, Part 3, Part 4
Well and so on. Who is interested and does not want to get into the same situation as in this article, you can find out a lot of interesting articles from this topic..
Here is a video of this repair:
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