Heater blower issues. Here's what I checked.
 

It's getting colder, and it's time to turn up the heat!

I pulled up the levers, and spun the dial to 3, and got nothing.
Actually, I tried 0,1,2,3 and none of the dial settings worked.
Footwell blowers are dead.

I took off both the footwell covers and checked the 2 fuses.
They were intact, and I verified continuity with my MM, to be sure.
So, they fuses are not blown.

I opened the engine lid and put the key into ACC (key buzzing, but engine off)
I pulled up the levers, and spun the dial to 3.
Engine blower is silent. (Engine blower was new 2 years ago)
I believe the engine blower motor should turn on at this point

It would be very rare for both footwell blowers and the engine blower to all stop working simultaneously.

Next step would be the switch?
But, what are the odds that BOTH red lever switches die at the same time?

So, this makes me think it might be some kind of relay downstream from both red lever switches.

What's the next step? Check the engine compartment relay?

SOLVED

Summary:

* I verified the footwell blower fuses were intact.

* I checked fuse #8 in the frunk was intact
http://i66.tinypic.com/29fzajk.jpg

* I tested my blower relay in another 911, and it worked.
* I also verified the 3 fuses were intact.
http://forums.pelicanparts.com/uploa...1290192285.jpg

* I verified pin #12 for that engine bay relay harness gets voltage.

* Then I found the culprit.
Blower motor was disconnected.

<a href="https://ibb.co/cwF4C0"><img src="https://image.ibb.co/i7cHX0/Capture.jpg" alt="Capture" border="0"></a>

I want to swap out this relay to see if this is the culprit.

But, how do I remove this?
Do I need to remove the entire bracket assembly?

The harness that the relay connects to seems like it's floating wet noodle
so if I pull it off, I don't think I can push it back on.

The way the relay works, to my understanding, is if the rear blower is not working the foot well blowers won't engage.

I had this issue, turned out to be a quick fix. The fuse for the engine blower was corroded.

I would look at the fuse and the relay. Both of these are the left of the engine. The relay is expensive to replace/hard to find so be careful with it.

Next step ?
Dig out the multimeter and start measuring voltages.

Do you mean the 3 blue fuses in the photo?
None of them are blown, and I spun them around to clean the contact point.
That did not fix it.

I do not know how to remove the relay box.
The harness base did not seem to be attached to anything,
so the whole attachment is very floppy.

http://forums.pelicanparts.com/uploa...1290192285.jpg

No idea what to test.
I need step by step directions meant for an idiot.

In the meantime, I will try to swap it for a known working one.

Woody, what you do is unscrew :eek: the bolt that holds the relay case to the board and then gently lift up - you will see that the harness plug for it is not attached to the board and there is some slack to that you can at least partially pull it through the board opening . . . then you remove the relay and will be able to re-attach another one since some of the harness socket will be up high enough for you to get a couple of fingers on it :eek:.

If there isn't enough slack, then you can loosen or remove the top two nuts :eek: that hold the board to the inner fender and the scooch it forward enough to give the harness some room to move (don't need to remove it). BTW, it is a good idea to disconnect the negative lead to the battery before doing any of the above.

Is your search function broken or you need that heat tonight ?!


Here... post even has a nice pic.

http://forums.pelicanparts.com/porsche-911-technical-forum/388445-carrera-removing-engine-compartment-heater-blower-2.html#post4156695

the first thing I would check is are you getting power to the blower motor. Then check the ground. Did you change the alt in the past, the ground for the blower connects to the alt housing. It does on an 88 any way.

Why is that electrical diagram for me?
It seems to be how to make a new double relay.
Not sure how that helps me "Dig out the multimeter and start measuring voltages."
I asked for directions on how to test my relay, not build a new one.

Everyone I know with a 911 has already mothballed their 911 off-site for winter
So, I am unable to acquire a 2nd relay.
Anyone know how to test the relay?
Otherwise, I can just spend the $500 for a new relay and hope that it works.

Check the ground #9 , power #12 , bypass #12 to #4 etc etc

then decide if you can afford $500 for a new relay or make one yourself.

Get on with it, Sugar !

Ok, I figured out how to remove the square relay box.
(I stuck my fingers underneath and base and pushed it up and out of the cavity.)

Now that I have the relay out, any idea how to test it?
I have a MM but barely know how to use it.

I have some old notes in here

What do you mean "check the ground #9" ?
I have a male pin on my relay box that says 9.
I also have a female #9 hole in the harness.
Which one are you referring to?

I have a MM.
Can you tell me EXACTLY where to connect the red and black lead?

Same question applies to the other 2 statements
"Power to #12"
"Bypass #12 to #4"
Can you tell me EXACTLY where to connect the red and black lead?

Here is more from another thread:

How do you open up this relay box?
I would like to see if anything looks broken inside.

Also, I only see pins #1-12 on the relay.
I don't see one post in 20 years with directions how to test the relay.
Weird.

Here is another post from Renn.
Can anyone help me translate this into directions for a n00b ?

Which is the positive terminal on the relay? Does he mean fuse?

https://image.prntscr.com/image/lKdX...6D52itPQcg.png

The numbers are on the relay you just removed !

I'm not going to hazard into any exact instructions over the interweb ... given this is electrical stuff, you can accidentally short something and cause further damage. Time to call a pro if this is beyond your comfort zone ?

Read the first paragraph in post #13

Might all be a moot point.
I installed a working relay from another 911,
and my heater still did not work.

I have 2 footwell blowers. Fuses are good.
I have 2 red levers, a dial from 0-3, and an engine bay blower motor.
If the red levers are bad, do they go bad together?
They work off 2 different switches, since they control independent footwell blowers.
So, it's next to impossible that BOTH red level siwtches would fail at the same time.

No idea where to go from here

Again, the footwell blowers will not work unless the main blower in the back starts working. Have you tried bench testing it? Have you tried seeing if you get 12V there once you crack open a red lever?

The main blower is brand new.

But, I will test to see if it's getting voltage.
(I predict the answer is no)
Which will not help me isolate the real problem

I need to look up how to test for voltage.
Have not done it in a few years.

Does anyone know how to test if the relay is getting power?
If it is not, that points to the levers.

20 years of archives,
and I could not find a single post on how to test the red levers.