Common fault - would only work flat out on setting 4. Other resistors dead.

Scrappy had no 323's but had two Mazda 6s.

'06 reg was 2.0 TD with blown turbo. Took resistor out and it was the later type with longer 'card' AND
different plug ... but same coloured 4 wires.

There is room in BJ for longer 'card', hole centres on mounting are the same but you obviously have to solder/heatshrink newer plug on and also file a small bit of plastic lug off to make mountings match.
All 4 speeds now working.
Pic. below is original 'short' type (note shape around righthand fixing hole)