Volvo FH 460 (2010): Adblue Heater No.2 Error - Resistance and Voltage Measurements

Hello, I have a problem with the adblue heater error No. 2 in Volv FH 2010. The computer shows a heater defect, after measuring it, the resistance is 7 ohms (the tolerance of this cable from what I read is from 8 to 15 ohms) and now the question is whether with such a small the difference will cause an error? I measured the voltage on the cubes of this cassette from which all the wires to the heaters come out and there is about 24 volt everywhere and there is 15 volt on the cube from the heater No. 2 (the key is turned on the ignition) and after starting the car, the voltage on the black heater cube number 2 drops to around 7 volts. Is this normal?
I dismantled the cassette that is next to the adbue pump, but all the wires are visually ok. I do not want to replace the heater blindly because I feel that I will throw money down the drain and the problem is somewhere else.
Will someone tell you how to bite it?

I would more consider why scr wants a heater during the summer vacation. Maybe one of the temperature sensors is out of order, or there is moisture in the cassette

Gun 20 scr will want a heater during the holidays because the system checks the operation of all elements, even though it will not use it for heating. A damaged heater will not limit the power in summer, etc., while in winter it is possible.

Can I connect the working heater No. 3 to the heater No. 2 socket, which displays the error? (it is known that the cubes do not fit, but I would fasten them with crocodile clips to the plug) If this would eliminate the error, I would be sure that the heater No. 2 should be removed and carefully traced for damage to the braid. Not the adblue driver?

You cannot damage the module because it has internal protections. On the other hand, replacing the heaters may not give the expected effect in the form of wandering or disappearance of the error. You need to know that the heaters have different lengths, therefore their resistances are different, swapping places may not facilitate the identification of the fault.

Disconnect the heater near the module and ring the meter.

There, checking the meter buzzer will do nothing. Ok take a good meter and do the resistance measurements again:
Heater 2 (yellow wire, black pin) 8-15 ohm
Heater 3 (red wire, gray contact) 8-13 ohm
Heater 4 (white wire, blue contact) 11-15 ohm
You have already taken the measurements, but spray the plugs with the contact and check everything again.

I will check the resistance of all heaters once more, but I will buy a better meter because I checked the usual one for PLN 30. Of all heaters, only two emit an error because it has a resistance of 7 ohms, which means that it does not fall within the range of 8-15. I will measure and write. Thanks in advance for all suggestions and hints, because in my area, the adblue repair is a month waiting for the guy to do this.