Ok the circuit is as follows Control head to the blower resistors to the blower motor, the blower relay is behind the blower motor and its only function on this system it turning on or off power to the motor when hit with a small voltage if this was out your motor shouldnt work at all. Since The system only operates on level 3 and you replaced the resistors as far as the schematic shows the only things in common with those 3 is the control head in the dash, the plug that connects to the rear of the control head and connector C205, The connector number c205 you see on the schematic is suppose to be behind the left kick panel and is light green.
Heres a copy of the schematic for you to see what I am talking about
Hope it helps
Its the plug more then likely, The connections are probably corroded or oxidized. Worn plugs are rare unless they were brutalized by a mech working under the dash. I would clean the connector pins and the matching pins on the head. Use an electrical component cleaner check over the plug and see if the plastic is damaged in any way. To clean the plug I would use an old toothbrush then blow it dry after finished If needed you can also expand the pins in the plug to make the connection better. The best way to do this is take the beauty cover off the front and remove the head Then you will have full access to the whole system.
This is a pretty basic blower schematic so yes it should be the same for an 02. If level 1 and 2 are not working, the most common problem is the blower relays/connections to the relays. Bigjeep also has a great point, the switch in the head and the connection to the head are also possibilities. If you have an ohm/volt check the voltage going into the relays and out of the relays to see if they is output ans input, they narrow it down from there.