SPS40 E32 RU/31. Goes in cycles, one of the heating element relays does not work ⇐ Bosch

[chinamobil]

About 4 minutes after the start of operation, one heating element relay clicks (right in the photo).
The second (left) relay does not work because... no voltage is applied to it. Therefore, the heating element naturally does not heat.
The first relay turns off after about 1 minute, all the LEDs on the front panel blink, and only the first relay turns on again, then turns off, and everything repeats endlessly.

The heating element is working, 20 oh, there are no leaks to the ground. There is no visible damage on the board.

What I tried:
1. I turned off the heating element.
In this mode, not a single heating element relay even tries to operate; apparently the PMM sees the wrong resistance in the heating element circuit and turns it off altogether.
However, the program runs completely and does not loop.
Everything seems to be normal, but the water is cold and the dishes are difficult to wash. I tried to connect the PMM to hot water - the result is also not satisfactory, grease remains on the dishes, because... The PMM does not have time to collect hot water (first it drains from the cold condensation tank, then it cools down from the pipes, and when the hot water actually starts flowing, the water intake is already completed).

2. I manually closed the second, non-working relay. It closed constantly until the PMM was turned on. (this relay is at zero, not in phase, so in my opinion it is safe)
Strangely enough, in this mode the first, working, relay of the heating element again does not even try to work. Why, I can’t understand. How does the PMM see that I forcibly closed one of the heating element relays, if it doesn’t even try to turn on the second one?

Tell me, what else can I try/check?