Mazda B2500 Wl Turbo Heater Problem

I have a problem with a Mazda B2500 Wl car, the preheater burn in a very short time and in the morning when this cold fails, Ise some online tests of the heater and notice that the normal energy and normal brand arrives the indicator signal on the board but when lighting the car the heater continues to function as for 3 or 4 minutes I do not know if this is normal in this car because in the others only it is He knows about the subject, I would appreciate some information as if it is normal for him to continue heating so much time and what kind of heater I must use
thank you very much before hand greetings

Hello, the heaters must measure 0.75 ohms the time that the lines have been activated, I have seen it but in current models I have even with the already heated engine there is the possibility that Buelva to use if that was the case I recommend looking in the workshop manual the type of heater that applies I am almost certain that the problem is the heaters, greetings.

Ok friend thank you very much I will look for the manual of that engine