Heater Blower in 3&4 Not 1&2
 

Hello All.

Lots to look at on this ol thing. 1986 S3

I recently recharged A.C. , replaced dryer/receiver and have good cold air. Wasn't just with A.C. but with heater too - blower motor blows fast and furious on levels 3 and 4 but I get nothing for levels 1 and 2. Are there separate relays that split blower motor speed???

As usual, super grateful to even have a group to ask this question to. Thank You

No split or separate relays for the blower.

Everything goes through the resistor pack.

The most common issue is 'magic blower syndrome', where the fan occasionally goes to full blast all by itself for a few seconds.

I'd guess you have a broken wire or something similar in yours. Might be fixable, might not. Replacements are available.

Thread on R&R of the pack (and a lot about magic blower):
https://rennlist.com/forums/928-foru...ic-blower.html

Hmm. No full blast out of the blue issues here. The fan works normally in the highest 2 settings. Not at all in the lowest. I wonder what's going on?

Does the resistor pack produce resistance differences for individual settings on the dash control,,, regulating the constant 12v? I guess my question is, is it the resistor pack thats responsible for denying or delivering different voltages to the blower? I HATE electrical issues, lol. Lost in them

I would replace the resistor pack as it is the only thing that controls speed outside of the switch on the headunit itself.

They're all starting to fail at this age anyways.

Yes. The pack has a selection of resistance circuits. Each position on the dial makes the current go through a different path. That's how the fan is regulated.

The 'magic blower' syndrome is because of the 'safety circuit' that has a bi-metallic strip that closes the 'no resistance' path when it gets too hot. The fan then blows full speed and cools the pack off, while generating no extra heat. The resistors create heat when they are being used, and the pack is in the HVAC duct, so the fan speed affects how much air goes past it. Magic blower appears most often when the fan is running at the lowest speed. Least airflow and most resistance get the pack the hottest.

I would suggest following the thread and pulling the pack. I'm going to guess (and it's just that) that you have a couple of broken wires in the pack. They may be fixable. Or maybe not. In either case, you need to take it out and check it.

Position 1 puts three resistors in series with the blower, position 2 eliminates one of these, position 3 goes through the remaining resistor, position 4 bypasses the resistors and applies full battery voltage to the blower. So sounds like the second resistor is open circuit and gets bypassed in positions 3&4.

Thank you Joe, Gaz and The Forgotten!!!

I've gotton a little more familiar with where things are in that wiper space where everything is jammed in and have located the resistor pack plug set... Happy to report that the boot connecting the two parts of the vent is subtle and soft/flexible. I was afraid before taking a look that it would disintegrate if I messed around with it.

I'll pull the plug and take some measurements, maybe go on to pulling it out and having a look. Maybe my problem is at and under the dash with the knob or wiring harness, maybe it's with the pack. I'll be hoping it's the former,,,, I just saw the cost of the damn pack 🤤🤤🤤

Love this site... Thank you all so much.
"Resistor Pack"!!! I never wouldah thunk it!

Not solved but some good things
 

Well whaTahya know???

Head scratching time. The type one does when one doesn't wanna spring for $80, $90,,, or 100 and sumpthin bucks on a new something,,,, or other !!!

In all seriousness, I took out the blower, got it in my hands, and that was the problem. Stiff, creeky and fighting the spin. When I took it out it would only spin (struggling) in setting 3 and 4. Spinning it by hand i could see why. Must have pulling real amps...

Took it, applied some goose greese (marvel mystery oil because I didn't want anything that would turn to gum over time)... Put a pool in what I can only call "wells" where the shaft meets the body of the blower, turned it by hand a while, repeat on the flip side, turning it by hand as it loosened up. Plugged things back in with everything laid safely across the intake plenum accordian, put the key in the dash, turned the setting to zero and slooooowly, on zero, it started spinning. Good! Spun faster on 1,,, nothing on 2,,, 3 and 4 like greesed lightning. Good!

On 1 and 3 the at first the resistor coils slowly turned hot cherry. On 4 not so much. Then i took a small pair of needle nose and laid the broken sections of 2 coil resistor over each other on the pack and BAM, 2 spun. Minimal contact, cherry red.

Temporarily I reassembled the fan and pointed the blowers flow over the resistor pack while testing which canceled out the cherry red resistors on all settings. Good!

By hand I unstuck the recirculation vent and it now will open and close with a nice soft thud when disengaging. Good!

I just tried to put the bogus solder I have over the overlapped sections of the 2 setting resistor wire coil. It just ROLLS off like water off a duck. Not sure what to do. It seemed to work fine as is and I think that's what it will be for now. 1, 3 and 4 are fine and 2 works with the crossed wires,,,, for now. Maybe, if 2coil gives out, or I have the doe, I will spring for a new fangled pack. We'll just have to see what comes first. To me, getting the rear ABS corrected (and many other things) is more pressing.

I wouldn't have known how to do or approach ANY of this with out you all. Much much much obliged! Really and as usual. All this took just over an hour with all the info I gathered reading the forum today!

Thank you all. It's not solved but I know what I got :)
https://cimg8.ibsrv.net/gimg/rennlis...677e565baa.jpg
The emergency contact to fight over heating conditions was permanantly touching 3 of the 4 resistors BUT the fans never ran full blast??? I dont get that. I pushed it down and away anyways.
https://cimg9.ibsrv.net/gimg/rennlis...525d12ddbf.jpg
Number 2 coil fried.

https://cimg1.ibsrv.net/gimg/rennlis...9f22a73f9b.jpg
Recirculation vent finally opened.
https://cimg8.ibsrv.net/gimg/rennlis...a15896f38a.jpg
Spin Doctorzzz

https://cimg8.ibsrv.net/gimg/rennlis...4eed6d2d40.jpg
She will have NO solder... It is what it is. The wrong solder perhaps or,,, i dont know what im doing!?

Good to hear you found the issue.

Soldering is a bit of a skill. If the solder isn't 'wetting' the wires, either they aren't hot enough or you need flux.
There are some good tutorials available, but the easiest solution would be to find some radio control hobbyists. 20 years ago, I'd suggest Amateur Radio (Ham) guys, but they are fading away.

Those types usually have good soldering skills.

Hi Joe... You mean the wire itself needs to be hot? And, is it a special kind of wire for this application? Considering the heat the coils deal with...

Forgive the simplicity of the questions and yes, aybe its YouTube and Google time.

One other question...

I now see the recirculation situation,,, but where is the outside ait coming from? Is it not filtered?

I don't think you are going to be able to solder the resistor back together with conventional lead/tin solder. The resistor is probably made of nichrome wire and requires a much higher heat to join. Even silver soldering might not fuse it back together. I suggest, in a pinch, tightly crimp the ends together in a bit of metal sleeve, like this:
https://cimg3.ibsrv.net/gimg/rennlis...40436dd1be.jpgWith a good mechanical connection, it might last long enough to allow for use until you can get a proper replacement.

Hi J, Thanks for the tip, idea... and I hear ya on the material not taking a joint... It's almost like it repels it

I was looking at similar bits online as your photos... Not sure how to buy the size I'd need. I HATE online shopping for that reason. Other concerns, and I'm NO electrician,,, is that the clip would drive up resistance inline and then, that that type of clip would contact neighboring coil spinz and shorten the current travel thus lowering resistance...? As you know, it's very tight. But again,,, i am NO electrician.

If you know,,, do those tabs (see pics) pry up. I've tried but if they do, damn, they are tight. Worried to break them. I read thru a thread where a guy said he had some resistor wire around, he found the proper wire, spun a new coil and crimped it in. I would LOVE to do that as a solution...

The ability to save $80 bucks here $60 bucks there is huge for me in this saga... There's 100 places to spend $80 bucks (and more and less) on this thing, lol

Just make sure that you are saving those bucks on non-essential items, ie., non-safety items. You don't want to buy lowball parts or products that when installed on your car won't get you home safe and sound.

(not saying you would do that.......just reminding) :)

Heard and understood... A well placed reminder! TY