Landseer

How does this work? 84 USA.

Does the resistor heat-up another "leg" for each notch of lower fan speed?

More importantly, does the resistor NOT get hot if operated at full fan?

Daughter called from the side of the road a little while ago. Wood/leaf smoke filled the cockpit via the ductwork.

She needs to drive home tomorrow in the car (3 or 4 hours ride) and may need heat and/or defrosters along the way.

M. Requin

With the blower control on full the connection is straight to the blower, so the resistors should not get warm. If you wanted to make sure tinder in the ductwork doesn't ignite, I would either put up with a chilly ride, or with the heat on full just turn the blower on (at amx) for a few seconds at a time to get the cabin to a tolerable temp. If I'm wrong I hope Alan chimes in.

Landseer

Looks like the fan is automatically operating at lowest speed with car running, if / when the HVAC sliders are not full left.

So I'll tell her if the sliders are moved, she must use full fan.
Defrost mode automatically gives full fan.
And thirdly, if it lights-up, walk away.

M. Requin

One other thing, with sliders full left, if the fan does come on by itself, I would tell her to stop and make sure smoke isn't coming out from under the hood. There is after all a thermal switch in the resistor pack to turn the blower on in an overheat condition.

Mrmerlin

Chris you could let her do some investigating remove the cowl panel cover WX strip then bend down the rubber bellows on the airduct she may be able to look into the duct and see if there is any leaves that may burn.
More than likely it will be OK,
If she doesnt want to do that she could pull the plug off of the airduct at the center of the car this will remove power from the resistor pack

Landseer

Great point, I'll call her, she knows where the resistor pack plug is located at least.

Alan

The answers so far are correct - the fan always runs at slow speed when the HVAC is on (e.g. Speed 0 is not off).

Running at full speed does bypass the resistor pack completely.

You'll will get a little airflow even with the HVAC off so alternating between full fan & Off will probably be viable points - the heater core gets hot water when the HVAC is off...

Alan

86'928S MeteorGrey

I havn't dug into mine yet, but I get smoke with the switch in any position other than off. However, if I leave the switch off, and slide the control to defrost, I get working heat at least. She might be able to do this to get her home. I've been driving my car like this for over a month. I'm not going to have time to dig into my car until next week.

Yep, when the system fails, Heater core always gets full flow for heat. It's the Germans way of saying it's better to be hot than dead.

Mrmerlin

Mike pull the plug off of the resistor pack

Landseer

She's now 90 minutes out and has gotten your collective advice. Near Appomatax battlefield. Has cycled it a few times. Said the engine is throwing enough heat (MM's are a set of collapsing fords). Is ready to pull that plug if needed.

Landseer

OK, finally got to this. Smoke had completely filled the cockpit at one point.

I must have forgotten to clean-out this plenum.
Mouse nest. Resistor group. Not a good combo.

Enough tinder in there to have caused a REAL problem.


Hard to get it all out. Like a Billy Mays commercial, while cleaning, "And There's MORE.." Better pull the fan and do it right tomorrow.

M. Requin

Glad it turned out ok! I haven't had too much trouble with mice in the 928 (yet) but they sure did love my XJ40!

Mrmerlin

pulling the resistor group plug would have prevented a fire.
Pulling the blower motor out and cleaning the duct will do the same thing

Landseer

This turned into a project. Pulled the hood for easier access.

928mac

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