Climate control fan controller

Mpierick · Mpierick's Garage

My air cond fan control will only work on the number 4 (high speed). Positions 3,2, and 1 will not work. I have searched the different threads and could not find anything. Knocking out one problem at a time. Many more to come.

Thanks for your help. Mike

garylewa · garylewa's Garage

Have you checked your resistor pack?

Mpierick · Mpierick's Garage

No I have not. Where is it located and is it a DIY?

All I have done is checked a relay and fuses.

Thanks.

Dean_Fuller · 07-08-2012, 05:15 PM

Motor side of the firewall. About center. Will have to remove blower motor to access the duct area, Resistor pack fits inside duct and screws to outside duct wall with wire connectors. When it goes bad the blower motor will only run full speed. Its pricey too.

AirtekHVAC · AirtekHVAC's Garage

I'm with GARY and Dean, mike...probably the resistor pack.

Mpierick · Mpierick's Garage

Thanks for all your help. I will tackle this next. Thanks for the help.

Mike P

Dean_Fuller · 07-09-2012, 08:03 AM

Actually I agreed with Gary and was just trying to tell OP WHERE the pac was located. Does sound like the typical resistor pac failure.

harborman · harborman's Garage

Wonder if you could substitute one from an American car or truck. I had to replace one in my Ford. Probably full speed is no resistor, the 3 lower speeds go through various resistors. Should be easy to determine resistor values and wattage.

Mpierick · Mpierick's Garage

It is funny you should bring that up about the Ford. I have a Ford Pickup that just started to do the same thing. I bought a new controller this past weekend and replaced it with no luck. I guess it also has a resistor pack.

harborman · harborman's Garage

Quote:

Originally Posted by Mpierick

It is funny you should bring that up about the Ford. I have a Ford Pickup that just started to do the same thing. I bought a new controller this past weekend and replaced it with no luck. I guess it also has a resistor pack.

Yes, resistor pack inside intake air chamber. It rusts out from humidity. I had to replace the resistor module and also a new cable with connector as it also burned. This was in my Expedition.

paris · 07-09-2012, 11:37 AM

Had to do the same job on my 98 Ford ranger missing the lower speeds had high, the one on my ranger is under the hood and the elements get right to it no protection

1980 euro 4.7
1959 356A coupe

Mpierick · Mpierick's Garage

Thanks for all the help. I wonder if I can get a deal if I buy two?????

Great thing is that I learned something today.

Mike P

garylewa · garylewa's Garage

Hey Mike,
This is an easy DIY, it's just located in an awkward location.
There are four small wire coils of differing thickness mounted on a what looks to be a Bakelite plate. The wire coils are crimped to the plate and the plate mounts using two screws.
I tried to rebuild my resistor pack using wire and coiling it to match the resistance needed and it worked for a couple of months only to have the new wire "melt" for lack of a better word. I bought a new pack on eBay and no problem since. I also removed a pin from the electrical connection so when I shut the fan off it is off. Porsche keeps the fan on a very low speed even when the control unit is set to Low.
If you need any more help feel free to post. I will take some pics for you if you need a walk-thru.

Mpierick · Mpierick's Garage

Thank you Gary. I am all for trying to fix the pack at least once and in the meantime look for a pack that I can afford.

This project has been fun. Running into opportunities at each corner. I am impressed at all the help that is offered by people all over the world. I cannot imagine tackling something like this without the INTERNET support.

harborman · harborman's Garage

Quote:

Originally Posted by Mpierick

Thank you Gary. I am all for trying to fix the pack at least once and in the meantime look for a pack that I can afford.

This project has been fun. Running into opportunities at each corner. I am impressed at all the help that is offered by people all over the world. I cannot imagine tackling something like this without the INTERNET support.

One thing to keep in mind if trying to substitute the resistors is make sure you have proper wattage of the resistors. If possible in this application go higher wattage. Normally wire wound resistors, as we are only dealing with DC current here. Maybe a FORD part will work!!! Not in a Porsche, I am bad now!

Alan1974 · 05-14-2014, 06:59 PM

I have a 1990 928S4 and also have the fan blower problem. I read on a forum that if you bridge 30 and 87 on the relay with a fuse in between the fan speeds should operate on 1 to 4. Prior to doing this and with this test the fan still only blows in the defrost or position 4 setting. nothing on 1, 2 or 3. Does this point to the switch or the resistor pack under the hood in the hvac system? Any help will be greatly appreciated. Also how to test the various items to eliminate the problems and identify them.

Secondly, will adding the daytime running lights relay enable the lights to function as daytime running lights or are further mods necessary?

Alan in AZ · 06:02 AM

I don't know where you read that but its a total bunch of crap - it may solve a problem of no fan operation at all but not what you have.

The only things that control the slower than full speed mode selection is the Blower Resistor Pack & the Blower Switch.

These switches are quite reliable and speed 4 works - so its connected.

This almost certainly means the blower resistor pack is faulty.

Yours uses the middle version - there are 3 types that are not all pin compatible. Early versions have a parallel bypass thermal element, if the pack gets too hot the themal element switches to speed 4 (known as the "magic blower"). Middle versions have a series cut-out thermal element, when it gets too hot it shuts off the blower (sometimes permanently). Final versions have no thermal device, are mounted outside the plenum and are truly off in speed 0) Make sure you get the correct type. If you could locate a suitable thermal element/switch (normally closed, opens at ?? C) you could probably repair it. Since this mounts to the plastic air plenum I'd assume <100C for the spec.

Adding a DRL relay (not all years) will get you the front foglights on all the time the car is running - so this makes the fog switch redundant - no other lights are involved. You need the DRL specific relay - NOT a generic one (a generic one will most likely cause damage - it has before).

Alan