[jracevedo]

Hello!
My 968 air conditioning fan have four speed, and only run at full speed. What can I do?

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[Anchorman]

My recollection is that this is the symptom of a failed ballast resistor. I seem to recall someone posting about this in the last week or so - including photos. Do a search for "ballast resistor" - hopefully that will take you exactly where you need to be. It's an easy fix.

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Here it is... http://www.968forums.com/index.php?showtop...60&start=60
go to post #74.

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[smshirk]

[quote name='Anchorman' timestamp='1241194413' post='71177']

My recollection is that this is the symptom of a failed ballast resistor. I seem to recall someone posting about this in the last week or so - including photos. Do a search for "ballast resistor" - hopefully that will take you exactly where you need to be. It's an easy fix.



Welcome to Forums.



Here it is... http://www.968forums.com/index.php?showtop...60&start=60

go to post #74.

[/quote]





I have a problem where the AC fan only works on 4, full speed. After some searching I came across this post leading me to pictures which I followed using the link above. I though great, but in my 94 Cab there are no ballast resistors in the slots as in the picture. My car has two cabin filters, one on of which is in the slot on the left where the picture shows the resistors. Does anyone know where these resistors are on a 94 Cab?

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[smshirk]

DayDreamer's post and attached pictures are for a 92 model. Anyone know when the design was changed, and if they moved these ac ballast resistors behind the bumper cover as they appear to be in a 993. I dont know for sure that's the case in a 993, but I found a DIY on another forum for upgrading the resistors on a 993 and the first step is to remove bumper cover. There are two ceramic resistors on my car under the cover just below the windshield. These are completely different design than DayDreamer's description, but I don't know if they are for interior fan switch or cooling fans. I can't find any other 50w resistors anywhere under the hood. Supposedly 944's were located behind instrument cluster. I've found a procedure for several other models but can't seem to locate ,the ballast resistors for the 968 anywhere. I have a 968 workshop manual but this stuff is not covered and I assume that means go to 944 manuals, which sends me behind cluster. I can't believe they would have moved them in the 92 968, then moved them back inside in later years. I sure hope not anyway.

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[flash]

unless i am misreading, what he is talking about is the blower motor, not the radiator fans. the ballast resistors have nothing to do with that. this is not a cooling system problem.

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[smshirk]

Perhaps you're right the initial question he answered referenced the blower switch in the interior. The poster had the same problem a I do in that ac works only on full fan speed. I

thought the fan resistors were the ceramics ones on the. Right side close to battery. At any rate, does your car have two cabin filters under the plastic cover between the windshield wipers?

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[flash]

the radiator fan ballast resistors are indeed located near the battery, on the firewall. they are not the problem in this scenario.



late cars had cabin filters. early ones did not.

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[jfrahm]

There is an overtemp reed style contactor on the fan ballast resistor assembly that can get cruddy and cause this problem. It can be cleaned with a drop or two of acid, like is found in some household grout cleaner or the like. Pin it open a bit with a toothpick and let the acid clean the contacts, then rinse and dry.



The blower fan resistor assembly slots into the fan assembly on the LH side (driver's in the USA.) All you can see is the connector, the resistors and contactor are not visible until the assembly is removed (2 screws, super easy.) 944 resistor assemblies have two contactors and 968s have one, as far as I know. They might be interchangeable so if you see two contactors, clean them both. Do not confuse this assembly with the ceramic puck resistors on the opposite side of the firewall.



In my case however when I had this problem my fan switch in the climate control unit was bad. It had broken inside and while it felt normal it was no longer making contact for the lower speeds.

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[smshirk]

Thanks Jfrahm, I think I can find it now. The picture of the 92 firewall really had me confused. I haven't had a chance to look at it in a while. My mother n law was living with us And passed away last Sunday. Weve had a houseful of people ever since. They all left today heading to Arkansas to spread her remains in an Indian burial ground. She wasn't Indian as far back as my wife could trace her family, plus the whole family is blonde with blue eyes, but they just let her believe it. I'm the dog watcher for a week so I should be able to get serval things done. I hope it's the resistor. I hate taking interiors apart. I probably have a bad window regulator as well, which just popped up after the AC switch. I suppose it's time for the electric accessories to start failing. It sure doesn't seem like a 20'year old car when I'm driving it.

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[ds968]

My fan switch now works only at the max ( 4th ) setting , and on top of it all it does not even function all the time..only sporadically . The other three settings are completely dead. So is the consensus that the problem is the resistor, as noted in jfrahm's post ?

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[MCL968]

That would be my first guess too. The fact that it works on high is strong evidence that the resistor(s) are toast.

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[ds968]

My mechanic is still troubleshooting the issue but he claims it can only be two things ; the resistor ( which is $ 80 ) , or the control unit ( which is $ 900 ) . So we're going to change the resistor first and then hope, pray, sacrifice chickens , etc that it'll fix the problem . If not, I'm hesitant to spend likely $ 1,500 for P&L on a new control unit and then find out that it may not solve the problem.. Could it be anything other than either a resistor or the control unit ?

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[MCL968]

I suppose that there could be a wiring issue, but the symptoms certainly point to the resistor. You can check the voltage at the resistor for each of the speeds to know for sure, or check the resistor resistance, but to do that you would need to know the values, so checking the input wires for voltage would be the best bet.

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[ds968]

Will have him look into that . I'll get a new resistor anyway though, $ 80 is a mere " rounding error " to the cost of fixing anything on these cars so may as well have a new part.

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[Bulti]

I believe I already accumulated about €5000 of 'rounding errors' over the years, lol.

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[ds968]

I keep thinking it's extremely unlikely it could be the control unit because if it was, the other functions ( heat / temp button , the AC switch and all that would not be working either .. ), nor would the last setting of the air flow switch for that matter. I am assuming of course that the control unit runs all those functions and there is not a separate control unit for just the air flow switch which costs $ 900 .. though I guess the resistor is separate for that particular function ..

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[Bulti]

Time will tell :-)

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[JWahlsten]

Sounds like the ballast resistors.  Typical behavior for the 944 series.  Doesn't sound like the control unit.

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[ds968]

I thought ( based on various other forum posts ) that ballast resistors are related solely to the cooling / radiator fans and they have nothing to do with the cabin air flow controls .. .??

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[Waylander]

The fan resistor is in the top of the air box for the interior fan, same side as the fuse box, two screws and a bit of mastic holds it in place, they are repairable.


If you have pollen filters it's right next to the drivers side one under the plastic wiper tray/rain shield

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