There is no power going into the blower motor switch in the MCC. The two wires that plug into that switch disappear behind the air box. I can't see where to trace it back any further. I assume that at some point it connects to the ignition switch.

Is there any other things on the same ign switch circuit that would not be working if it is the ign switch? (I think everything else is working). Which wires from the ign swtich can I test for the blower motor switch?

What or where can I test next to find where the power is not getting through?

Thanks.

There is power at the #16 fuse, so I assume that the problem is after the fuse.

I assume the power leaves the fuse and goes to the ign switch and then to the blower switch--- but I could be all wrong.

"I assume the power leaves the fuse and goes to the ign switch and then to the blower switch---"


No, the ignition switch is always unfused. It goes like this:

Ign.Sw. ==> fuse 16 ==> C19* ==> fan knob module ==> resistor block** ==> fan motor

*C19 is a 2-pin connector. From the picture in the diagrams, it looks to be somewhere up under the right side of the dash. Fan power goes thru on pin 1 (black wire)

** the resistor block is also on the right. It looks to be above the passenger's feet and probably not far from C19

With fan knob on 5, the resistors are bypassed but the red/white wire still goes to the resistor pack and back out to the fan.
The resistor pack has 3 connector plugs. The fan power (red/white) comes in pin 2 on the middle plug, and leaves for the fan via pin 2 on the lower plug (That's a guess. Could be vice versa.)

Those two plugs look fairly accessible for voltage checking.
But that's based on a drawing. I've never seen them myself.

Good luck,
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

So, if I have power at the fuse but not at fan knob module (fan switch), then perhaps the problem is at C19?

But does the wiring go from the fuse block in the central console over to the passenger side to C19 and then back to the fan switch in the central console? Seems like wasted wiring to go over to the right side of the dash and then back to the central console.

Thanks

I'm guessing at the location of C19. The pictorial isn't that explicit for all items.

C19 may actually be nearer the main controller, because C19's "output" also goes to controller pin 12. Perhaps as a signal that the fan is (or should be) ON.
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.