Heater not working on 401 kenworth

Wiring, schematic, electric al diagrams etc are basic contents of these online books they here on this website www.reliable-store.com Must check it out

does putting heater on hot prduce hot air.on full with fan on does it reduce temo?is ur radiator fan coming on? hard to give one answer.as dont know if its overheating in traffic or on the move?there could be air stuck in pipes slowing water flow.or a pipe/radiator blockage so coolant doesnt get to flow around engine so it gets hot.u could check radiator by touching see if hot or cold where pipes enter(prob switch off engine first) try bleeding system squeesing pipes to push air out

Sounds like you covered everything.
The fans come on at 220 degrees but the engine continues to get hotter ? Have you tried running the engine with the thermostat out to check for flow and blockages ?

Check the heater tap control is operating when you turn it on. Check the hoses into the cab for kinks and blockages. AS the heater is above the engine ensure that there is no air lock in the system

Culpilt can be thermostat valve or the pipe line blockage to the heater

With all the work done I'll assume you've bled the system of all air? You may want to check the shut-off valve in the heater hose. Also, was the thermostat replaced with the same temp thermostat? Just a couple quick thoughts. I hope they help! Good luck!

Firstly before commencing any new work , ensure that you do not have an air lock caused by replacing the previous various parts. Follow the pipe from the thermostat, with engine running and it should heat up when thermostat opens. Follow this pipe towards both the Heater matrix and the carburettor. Both should warm up slowly. Have the heating on inside the car to blow warm. Then feel the exit pipes from the Heater Matrix. The exit pipe should also heat up. If they remain cold the you have an blockage within the Matrix which can either be air or debris. To cure air, let car cool down and remove expansion vessel cap. Then remove exit pipe from heater matrix and hold pipe aas high as possible.....if air is causing the blockage then it will purge itself, when water starts coming out of Matrix, reconnect pipe and top up levels as required. If nothing comes out, the matrix is blocked, may respond to after market flushing treatments or may require removal (pig of a job) Do check before this that oil is not getting into water circuit (dark floating bits if mild, all light brown if bad)or vice a versa (white scum on bottom of dipstick)which would indicate blown head gasket is causing car to overheat!

The heater core is probably clogged, or the valve that lets radiator fluid flow through the core is not working.

Sounds like there may be an air pocket in the system.
Try 'burping' the system. If this still doesn't fix the problem, check the temperature of the heater core hoses (in and out) The inlet should be fairly cool, the other should be piping hot. If they're both cold; the heater core has an internal blockage.

Next, replace the thermostat with a winter (180-195 F) derivative.
Bleed the system accordingly, and keep me posted!