E30 Zone

hi guys i've had this problem for a while now. no matter wot speed i put the heater on it does not even attempt to work. it stopped working when i changed the engine from an m20b20 to an m20b25 initially i thought it was because i changed engine looms but i have since changed them back with still no joy. i have checked the motor which is all gravy. its getting a bit colder now so would like some heat. any help greatly appreiciated. also i have a drain on the battery which runs it down totally in a day of no use since the engine was changed and the elactric windows dont work unless the door is open. thanks Tim

Windows and heater fan are the same fault! Mirrors probably don't work either!
You haven't connected the unloader relays, K5 and K7, up properly to the starter motor after the engine swap.
Ages of car and engine?

both cars h reg one was a sport one was a 320 i se. how do you mean i connected up wrong?

The relevant connection on the engine loom is a black/green wire that goes to the starter motor.
First test is to remove relay K7 from the fusebox, and use a piece of wire to link together pins 30 and 87 of its socket. Does this make the heater fan and mirrors work?
Now do the same with K5. Does that make the windows work?