It is a bank of resistors which plugs into the side of the heater casing.
trace the feed to the blower motor then follow it backwards till you reach
the output wire from the resistor bank. If you try the other wires on the
connector you will find which one(s) have 12V on them when the switch is
changed from off through the other positions. If you have no 12V at all then
check the wiring from the fuse; if you have 12V on some of the connector
pins then replace the resistor bank. You may be able to repair it unless it
is of the later type which is composed of solid ceramic insulated resistors.
The earlier type was made of wire loops of which one would go open circuit.
Haynes or Chilton manuals will show how.
All the best, Peter.
700/900/90 Register Keeper,
Volvo Owners Club (UK).
> hi everyone in volvo land.just landed here from planet peugeot after some
> t-=t wrote of my 405 deisel pug (b3£%^&d).anyway i have just adopted a 940
[quoted text clipped - 5 lines]
> the resistor.how do you check it to see if it f^$")d or working.and what
> are my other options