The 2 higher speeds run off a separate fuse from the 2 lower speeds.
This fuse also powers the compressor clutch and the radiator fan low
speed when A/C is on. This fuse is very important obviously.

The fuse in question lives inside the lh rear pillar cover. It is really
a bare metal strip screwed at each end to the base of a relay holder in
that area. The metal strip is the fuse. That immediate area is prone to
cooked wires so look at it carefully even if the fuse is good. Use a
voltmeter to check the fuse and the wires.

Mark

John Goubeaux wrote:
> Folks,
>
> I have a situation on a 90 (with factory AC)   where the AC fan works on
> the first two settings but nothing on the 3rd and 4th. I have already
> trbl shot the switch up fwd and it IS good.
>
> So is this a problem with the evaporator fan resistors ?  or someone
> suggested that:
>
> "There are two fan resistors, one for each fan motor. Unless they both
> burned out at the same time, they are probably not your problem, its
> more likely you have a problem with the evaporator fan switch and its
> associated wiring."
>
> I'm not sure if this is referring to the wiring back in the lh rear and
> if both resistors burned out would the fans run at all?
>
> The compressor is not working (yet) so I can't actually "fire the system
> up" properly and I'm not sure if this is the source of only two speeds
> either.
>
> Can anyone with knowledge of how the system works steer me in the right
> direction?  What am I missing?
>
> Many thanks ....
>
> -john
>
>