Blower motor wiring

[farrier]

So the yesterday when I made a stop and before I turned it off, the blower motor worked fine except on the highest setting.
When I started it up there was nothing at any speed setting.
Tested the motor, it's good.
This is a '81 Rabbit diesel pickup w/ac. Although ac is disconnected.
The two wires that run to the blower are the brown (ground) and red/yellow (no juice).
The R/Y wire goes into a cluster of taped up wires and comes out to a couple of relays (?) on either side of the black heater box.
But my Bentley manual shows a hot Y/BK wire coming from the blower that forks off to the fan switch and I'm guessing a resistor.
So I can't find the source of the R/Y wire and were it gets its juice.
I do have juice at the fan switch on all 3 wires going out.
Any ideas?
Thanks.

[colby]

Usually when the resistor goes bad you get only high speed. Since you have nothing, I would say check the fuse, if you haven't already. Other than that, thats strange.

[farrier]

Colby,
I've never had high speed work for me. But it always warmed up nice so I didn't worry about it.
Yes fuse is good, and there's juice at the fuse box.

[colby]

Well, you have power to the switch for the blower, so thats good. Do you have a spare switch?

[farrier]

No spare switch. I guess I could test to see if it's bad with a jumper wire?

[82vdub]

Switch works as it's got power, and it's sending power out on all the fan switch postions. The likely culpret is the blower motor resistor. Go get another one and install, and your fan will likely work.

Whatever you do, you have to fully install the blower motor resistor in the airstream. If you have it hanging and want to test things and turn the key on and move the fan switch, you will fry the coils. Blower motor resistors are usually pretty expensive too, at least for what they are made of and what they do, IMO.

[bscutt]

There is a relay that controls the highest fan setting an A/C vehicles. Along with that there's a connection above the throttle pedal where it all connects. Do not remember if that's where the relay is or if it is in the fuse panel.

Mine did the same (only 3 speeds) until I found the relay and connection points. Unplugged them then replugged and it all works fine.

[farrier]

Is the resistor the little rectangular gizmo that's attached outside of the black heater box, underneath the dash?
It has 4 wires going to it.
The blower motor has 2 wires running from it which goes to a detachable connection.
When I disconnect and put juice to it, it spins freely.
Thanks.

[surfcam]

I know on the Mk11's the resistors are on the blower motor. Maybe the Mk1's are the same. I think the high speed doesn't go through any resistors. That's why when the resistors burn out your usually left with just the high speed. A jumper wire can come in handy to eliminate a relay or switch or something else.

[82vdub]

Yes, the blower motor resistor would be the device that's in the air box beneath the dash as you describe. You should be able to take a reading of the resistances through each one, and if they aren't open, then they are (or should be) working fine.

[Dallas]

The resistor will look like a ceramic tube with a coil of wires wrapped around it. It does get VERY hot when fan is running. That is why it is under the blower motor in the air box. The 'little ' black box may be a relay. Not on my car as mine does not have a/c.