Did you change the pineapple heating box or not?

The warm air blows the heat from the warm air small water tank into the cab through the blower. If the air volume is not enough or the distribution of cold and hot air is not good, the heat of the small water tank of the warm air will not be radiated, and the temperature of the warm air will not come up. At this time, first check whether the filter element is dirty and blocked, clean it, and replace it in time if necessary; Then check the operation of each gear of the blower, and each gear must reach sufficient speed. If the knob is set to the warm air position, the air volume is large enough and the wind direction is normal, and the cold air is blown out, check whether the cable of the hot and cold air control flap in the warm air box falls off, whether the warm air impeller is damaged, whether the flap falls off, etc. After troubleshooting, the warm air is normal.

I hope it helps you!