Carrera - Removing Engine Compartment Heater Blower

[scarceller]

Originally Posted by Jaskas

Thanks. I will try those trick out today! ( I have no other life than Porsche in Sweden )

This may help:



The parts in yellow are the optional Auto-Heat parts.

So simply put the rotary switch in Pos #3 and hot wire 12V to pin #4 (with controller disconnected) and the 2 front blowers should come on, if they don't then the 'front trunk aux. relay' is bad. If they come on in pos #3 then test the other 2 positions. This test will test the rotary switch, the relay, the resistors and the front blowers. If this test works then the problem is somewhere in the controller or the signals to the controller.

[Jaskas]

- be sure you have 12v at all times on pins 3, 7 and 8. -> OK
- Then pin 12 should have 12v with key in 'RUN'. -> OK
- pin 2 must be ground at all times ->OK
- pin 9 is the pin that goes to ground to activate the heat controller -> OK

Another quick test is to unplug the heat controller from the harness and hot wire 12V to pin #4, this should send the power up to the front footwell blower rotary switch, if the switch is in pos #3 and pin 4 has 12V the blowers should run.
-> On max ( 10) footwellblowers worked, on minimun (0) they didnt. I have to still test those on 8 and 9.

[Jaskas]

I hotwired the pin #4 and the blowers worked with lower speed with positions 8 and 9 in switch. Max speed in position 10.
In other positions they didnt run at all.
So they should work OK.

So could the problem be in the heat controller relay for footwellblowers?

[scarceller]

Originally Posted by Jaskas

- be sure you have 12v at all times on pins 3, 7 and 8. -> OK
- Then pin 12 should have 12v with key in 'RUN'. -> OK
- pin 2 must be ground at all times ->OK
- pin 9 is the pin that goes to ground to activate the heat controller -> OK

Another quick test is to unplug the heat controller from the harness and hot wire 12V to pin #4, this should send the power up to the front footwell blower rotary switch, if the switch is in pos #3 and pin 4 has 12V the blowers should run.
-> On max ( 10) footwellblowers worked, on minimun (0) they didnt. I have to still test those on 8 and 9.

On the auto-heat rotary switch I guess it has 10 positions, not 3.
Pos 0 is off and if in this position then blowers will be off.
Pos 10 is hi-speed and you said this works.
Pos 1-7 is lo-speed and this uses both resistors
Pos 8-9 is Med-speed this uses one resistor

So if pos 10 works but 1-7 or 8-9 don't I suspect you have a bad resistor.

Next question: if you leave switch in Pos #10 and you have the controller connected do the blowers come on (full speed)?

[scarceller]

Originally Posted by Jaskas

I hotwired the pin #4 and the blowers worked with lower speed with positions 8 and 9 in switch. Max speed in position 10.
In other positions they didnt run at all.
So they should work OK.

So could the problem be in the heat controller relay for footwellblowers?

When you jumper pin #4 you are simply leaving out the controller and testing the blowers, front trunk relay, resistors and rotary switch. We need to be sure all this up front stuff works before we assume an issue with the controller.

First, Rotary switch Pos 0 should have the blowers turned off.
So, are you saying rotary switch pos 1-7 do not run the blowers? they should run very slowly, they may be running and you can't hear them. Put your hand on the blower(s) to feel if they are running, we need to be sure. If they are not running in pos 1-7 then you have one bad resistor.

[Jaskas]

Originally Posted by scarceller

First, Rotary switch Pos 0 should have the blowers turned off.
So, are you saying rotary switch pos 1-7 do not run the blowers? they should run very slowly, they may be running and you can't hear them. Put your hand on the blower(s) to feel if they are running, we need to be sure. If they are not running in pos 1-7 then you have one bad resistor.

I have to check this... back to garage...

[Jaskas]

Originally Posted by scarceller

First, Rotary switch Pos 0 should have the blowers turned off.
So, are you saying rotary switch pos 1-7 do not run the blowers? they should run very slowly, they may be running and you can't hear them. Put your hand on the blower(s) to feel if they are running, we need to be sure. If they are not running in pos 1-7 then you have one bad resistor.

Pos 1-7 nothing, absolutely nothing

When i did turned on manually the footwellblower relay in the controller, they started running
The one just left of the reed switch text



Next question: if you leave switch in Pos #10 and you have the controller connected do the blowers come on (full speed)? -> Only when pin 4 is jumped

[Jaskas]

And where are those resistors?

[scarceller]

OK,

You may have 2 separate issues:

- issue #1: pos 1-7 does not run blowers with pin #4 hot wired. This most likely is a bad resistor. They are located behind the passenger foot-well board.

- issue #2: if you connect the controller and do not hot-wire pin #4. Turn rotary pos #10 key in 'RUN' you should have heat and blowers running full speed. But one other question is, how do you set temperature with auto-heat? I'm not sure of this.

Here's another quick test to try:
With key in 'RUN' rotary switch in pos #10 and controller pluged in try grounding pin #9 and this should activate (turn on) the controller and the blowers should run. If they do the controller is working just fine. The issue is somewhere in the Auto-Heat section and not the controller.

[Jaskas]

Originally Posted by scarceller

OK,

You may have 2 separate issues:

- issue #1: pos 1-7 does not run blowers with pin #4 hot wired. This most likely is a bad resistor. They are located behind the passenger foot-well board.

- issue #2: if you connect the controller and do not hot-wire pin #4. Turn rotary pos #10 key in 'RUN' you should have heat and blowers running full speed. But one other question is, how do you set temperature with auto-heat? I'm not sure of this.

Here's another quick test to try:
With key in 'RUN' rotary switch in pos #10 and controller pluged in try grounding pin #9 and this should activate (turn on) the controller and the blowers should run. If they do the controller is working just fine. The issue is somewhere in the Auto-Heat section and not the controller.

issue #1: i tried to measure the resistors, but it seems i measured the ones for freshair blower, in the fire wall, in the luggagecompartment. ( i will test these tomorrow)

issue #2: yes they should be running at full speed, but they aren´t

your test: i kind of tried it, the pin 9 does ground when switch is activated...

[scarceller]

Originally Posted by Jaskas

issue #1: i tried to measure the resistors, but it seems i measured the ones for freshair blower, in the fire wall, in the luggagecompartment. ( i will test these tomorrow)

issue #2: yes they should be running at full speed, but they aren´t

your test: i kind of tried it, the pin 9 does ground when switch is activated...

Some cars did have the resistor pack in the front luggage compartment on the passenger side below the windshield. So you may have found them. Not sure what resistance they should be but they are most likely very low resistance (below 100ohms). Just be sure they are not burned out (open circuit).

Then the way the controller works is that when pin #9 goes to ground it activates the large internal relay, this relay turns on the rear blower and thus activates the reed switch. Then once the reed switch picks it activates the smaller internal relay that powers the front footwell blowers. So the idea is to ground pin #9 and see if the rear blower gets power on pins 5&6. Then once the rear blower is running then the smaller relay activates and you should see power on pin #4 to the front blowers.

So simply grounding pin #9 should first produce power on pins 5&6 then if the rear blower is connected it should come on which in turn picks the smaller relay and produces power on pin #4.

For testing the controller I suggest just keeping the Rotary switch on Pos #10.

Hope this helps.

[Jaskas]

Originally Posted by scarceller

Some cars did have the resistor pack in the front luggage compartment on the passenger side below the windshield. So you may have found them. Not sure what resistance they should be but they are most likely very low resistance (below 100ohms). Just be sure they are not burned out (open circuit).

Then the way the controller works is that when pin #9 goes to ground it activates the large internal relay, this relay turns on the rear blower and thus activates the reed switch. Then once the reed switch picks it activates the smaller internal relay that powers the front footwell blowers. So the idea is to ground pin #9 and see if the rear blower gets power on pins 5&6. Then once the rear blower is running then the smaller relay activates and you should see power on pin #4 to the front blowers.

So simply grounding pin #9 should first produce power on pins 5&6 then if the rear blower is connected it should come on which in turn picks the smaller relay and produces power on pin #4.

For testing the controller I suggest just keeping the Rotary switch on Pos #10.

Hope this helps.

This was the resistor in the luggage compartment:

It was easy to measure...

I have jumped the reed swich to eliminate it also. So the smaller relay should be activated always when the temperatur swich is in pos. 1-10 ?
And the from the swich you can choose, trough which resistor (s) does the current go trough... am i right?

more testing tomorrow...

[scarceller]

Yes,

That's the correct resistor. Looks like across the entire resistor is 2.3 ohms and this is for lo-speed. Then across another section it reads 0.85 ohms and this is for med-speed. Hi-Speed is NOT routed through this resistor at all.

Also, I did some more research on auto-heat and the rotary switch 0-10 positions sets the desired cabin temperature and compares it against the actual cabin temp which is measured by a sensor located to the left of the heat levers in the center of the dash.

This means that if the cabin is already warm enough then some positions (like 1-7) might not turn on the heat. Bottom line is your system may be working just fine. I think it needs to be real cold for pos 1-7 to turn the heat on.

So for now simply set to pos #10 and see if heat comes on.

[Jaskas]

Originally Posted by scarceller

So for now simply set to pos #10 and see if heat comes on.

I tested the pin 9 grounding issue once again. It is in ground when switch in positions 1-10, and no current to pin 4. -> FW-blowers wont work.
The engine blower works as it should, and it gets offcourse 12 volts...

When push the footwellblower relay in the controller manually down ( with a skrewdriver ) the FW-blowers work as they should.
So it think that the footwellblower relay in the controller is broken.
Can i replace it with something like this :

[scarceller]

I agree, you have a bad controller.

You can replace the ENTIRE controller with 2 relays like the one you suggest, see post #35 for howto wire them up. I did this modification in my car to simplify the parts in the engine bay and use 2 simple relays. I cut off the old harness and then wired the new relays. Be careful and DO NOT mix up the 2 yellow wires (pin 9 and 11).

Since you already have a bad controller you could gut it and simply wire the 2 relays into the old controller and not alter the harness, I suggest this approach.

Also, if you only want to run the front blowers and not the rear you will only need one relay, see the schematic in post #35

I also have a working controller I would sell if you want it, PM me.

[Jaskas]

Thanks again Scarceller!

I did your double-relay modification, and now everything works as it should.

[scarceller]

Originally Posted by Jaskas

Thanks again Scarceller!

I did your double-relay modification, and now everything works as it should.

That's great!

So do those relays fit in the old cover?

Also, you could purchase relay sockets for those style relays and simply let the sockets hang out of the old gutted relay. This way you can plug and unplug the new relays for servicing them. But I'm sure they will last many years without needing to be changed.

Glad your heat is now functional.

[Jaskas]

I was thinking of buying the sockets also, but they wouldnt fit the original cover. So now im hoping that the relays wont brake down...

[scarceller]

Originally Posted by Jaskas

I was thinking of buying the sockets also, but they wouldnt fit the original cover. So now im hoping that the relays wont brake down...

You saying the relays will fit inside the original cover?

[Jaskas]

Yesyes!
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