It is enough for the driver to set the desired temperature in the cabin with the handle of the control unit, the rest will be done by the system itself. For example, the position of the radiator damper does not need to be selected by moving the lever with your hand. This function is assigned to the micromotor reducer.


The control unit estimates the temperature in the cabin by the signal from the sensor on the ceiling near the ceiling. The system works, starting from the first ten, in general, not bad. But there were some problems. No wonder our motorists are wary of everything new, especially the fact that at least somehow complicates the design. The control algorithm also failed in this system: for example, when the passenger compartment warms up after a night stop in the “A” position of the handle, the motor goes to high revolutions, and then it drastically reduces them. Many, not having studied the instructions, suffered with the recirculation mode. It was not without difficulty that they mastered the “secrets” of the heater in service centers, first of all, due to the lack of suitable diagnostic equipment. It even reached the “accusations” of the heater control unit in the malfunctions of the engine control system.

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Having accumulated experience, including bitter experience, VAZ specialists hand in hand with colleagues from the Samara NTS company implemented a heater diagnostic system. Now the control unit (photo 1), the micromotor reducer (photo 2) and the interior temperature sensor (photo 3) can be interrogated with passion at any time. With the choice of a diagnostic device, they did not become wise. This is either DST-2M with the corresponding cartridge, or its more modern, programmable analogue of DST-10.

But we will disappoint the owners of the “ten” with an outdated version of the control unit (2110) with the “A” mode: it will not be possible to diagnose this system (on the right photo 1). The diagnostic system is designed for a new version of automatic control of the heater (SAUO) with block 2111 (pictured on the left 1). The one and this one are similar, but the modern one does not have the “A” mode, and there are four speeds. Blocks are not interchangeable - let the same connectors not be misleading. If you put a new one in place of the former, then when the cabin is warmed up, it will not open the damper, but, on the contrary, cover it.


For the diagnosis of self-propelled guns, the same connector is used as for engine control (from the bottom of the instrument panel, just to the right of the steering column). We connect the scanner, turn on the ignition - and having selected the "air conditioning" (SAUO) item, press the "enter" key. The scanner must contact the heater control unit - the arrow in the upper right corner of the display will inform about this (photo 4). If a cross appears here, there is no connection. The most likely reason is the lack of a wire connecting the K-line to the control unit. Check this - remove the block from the console (after removing the stubs adjacent to it); on the back of the unit there are connectors X1 and X2. Pin 12 of connector X1 must be connected to pin 7 of the diagnostic block - they are all numbered for convenience. If there is no wire, lay your own. You will need a small (about 0.5 m) length of wire and one terminal for the connector block X1. The work is simple, it won’t take much time. Made?

Turn on the scanner again. There is an arrow in the upper right corner of the display, which means that you can start diagnostics. First of all, let's look at the list of errors in the block memory.

Unlike the engine control system, a warning lamp is not provided here (“Check SAUO”). So we judge the malfunctions with the heater (in addition to the results of the poor work itself) by the reaction of the scanner to them: if any element fails, the unit will fix the error and write its code. In addition to the error item, the scanner displays the items already known from engine diagnostics: general parameters, parameters by groups, actuators. At the same time, you can check the block number and the recording date of the software.

Parameters by groups, in turn, can be divided into “user” and “default” groups! In other words, the matter of the diagnostician is to silently agree with the developer of the scanner and use the proposed groups or create your own, custom ones.