Heater backdate blower works only at 1 and 2

[midnight911]

The car is 1984 carrera with manual heat control.
The heater blower (footwell) only works at position 1 and 2. Nada at position 3.

Looking at this diagram i stole from a thread, seems the footwell blower is getting power from the relay in the front trunk when the knob is at the position 3? So, i should say the relay in the trunk is broken?

The blower works when the knob is at positions 1 and 2.

Please help me interpret this diagram.

thanks in advance for the help.

[midnight911]

it also helps if someone told me which pin at the heater control feeds power/ circuit when the knob is at position 3, so that I can check if the control has issues.

[aj88cab]

As you noted, FWB speed setting #3 runs thru a separate relay and fuse. the relay is on the front (trunk) relay panel, round relay closest to the windshield I think. The fuse for speed #3 is also on the front fuse panel, fuse #2 (25A). Check the relay & fuse. If the rest of the speeds work this is probably where the problem is.

[wwest]

Power for speeds 1 & 2 comes from pin 4 of the heat control module back in the engine compartment. Speed 3 comes from the front trunk relay AND fuse....

Since you are getting power from the heat control module for lower speeds that module is working CORRECTLY.

[midnight911]

very helpful and thank you.

yes, it was the relay. i swapped with another...the ac one as ac is not present...and got the position #3 working.

thanks again!