1998 a4 avant 1.9tdi no heater
 

help i've bought a car with no heating, seller says he bought it also with no heater so have no history on how it went or why. its an audi a4 avant 1.9tdi estate 1998 (b5). a/c pump has gone but also have no heater, blows out cold air. Have bled the system for ages getting the air out. Both pipes from radiator go hot.i know the a/c pump has gone but i've checked thermostat; brand new, changed head gasket, timing belt, still nothing. vag-com results say too many errors (excessive comm errors) on channel 08; auto hvac. Altered density etc, but cannot get any fault codes for this code number however i try. Only found errors on channel 35; centr. locks.16 in total, 7 of these were unknown error codes.
any ideas?