2006 STi Gauge turns off when Blower fan is turned on ::fixed::

[Ngrabau]

Ive recently gotten a strange come back of a 2006 Subaru STi that we just installed an HSF-3 v2 on. The car left in working order, or so I thought. I guess I just never thought to turn on the blower (HVAC fan) while the car was here.

Basically, with the fan in the off position, the system works great. The gauge comes on and the meth flows readily when the IDC requests it too. However, as soon as you turn on the Blower fan, (this is a "auto A/C" system), the gauge turns off. I've tested for power at the module and voltage is present and never drops below 12.5v. Both grounds are good and are spliced together before they meet the chassis ground. I've installed a bunch of these kits into Subarus before using the same power sources and never had any issues.

I've tried multiple power sources around the car, and event made an entirely circuit using a relay with no changes to the problem.


As the system turns off, you can here a relay clicking inside the module.

The SN for the module is: 100685 and was purchased new from Howerton Engineering about a month or so ago.


If I'm leaving out any crucial information, please let me know.

I'd love to suggestions on where and what to test internally to see if there are any potential issues with the module itself.

-Nick

[Richard L]

Possible causes:

1) This could be the start-up timer seeing a downward pulse and reset. You will not be able to see the pulse with a voltmeter becuase it can be a few milli-seconds long. I don't think this is the case,

2) If you hear a relay clicking, it will be the red wire of the grey harness loose 12V momentarily, Check this connection of this red wire, make sure it is not loose. This will also the reset start-up timer. Also check the termination of the grey RJ45 connector, make sure the plastic partition is not distorted.

I would like you to send the controller back to me, I love to find out the source of problem. I will just need one day and I will return it back to you.

Your information is good!

[Ngrabau]

Possible causes:

1) This could be the start-up timer seeing a downward pulse and reset. You will not be able to see the pulse with a voltmeter becuase it can be a few milli-seconds long. I don't think this is the case,

2) If you hear a relay clicking, it will be the red wire of the grey harness loose 12V momentarily, Check this connection of this red wire, make sure it is not loose. This will also the reset start-up timer. Also check the termination of the grey RJ45 connector, make sure the plastic partition is not distorted.

I would like you to send the controller back to me, I love to find out the source of problem. I will just need one day and I will return it back to you.

Your information is good!


Richard, As always, I greatly appreciate your help with this. I have been working on this all day and have made little progress.

I would love to send this unit back, please let me know where to ship it too. However, I don't think there is anything wrong with it. I believe the issue lies somewhere in the factory wiring somehow. Simply knowing that you've tested it will give me a little piece of mind on the matter.

I appears that nothing is loose at the moment. All my connections have been made using seamless, uninsulated butt-connectors and glue-shrink wrap. Shaking wires around doesn't seem to make any difference. Nor does moving the ground to a different location.

I've discovered some other interesting features of this problem while trying to figure this out. If I remove the blower fan relay, the system never turns on at all, even though there is still 12.6v measured at the HSF-3 module. Plug the relay, the whole system turns on!

I'm currently drawing power from a switched source that is on the front of the interior fuse box, a Yel/red wire that feeds power to things like the power mirrors, the accessory sockets, and a few other things. This is a very common wire, I've found, to get a switched 12v source from. I have used it on probably over 50 Subaru's to grab power for gauges. Its never been an issue before. I have also tried moving it to a different switched 12v source with no change.


Now, after all my testing I have the HSF-3 working, but I can't get the blower motor to turn on. I have a feeling that once I do, the HSF-3 will then go inop again.

This has proven itself to be quite a challenging issue.

Thanks again for your help.

[Richard L]

This is indeed very puzzling. I like to continue on some more diagnostic work if you don't mind. I have not had this happening on the v2 at all, thats why I am taking a special interest on tracking down the cause.

Are you using the wiring diagram for the 06sti on this site? Can you give me some help:

Where is ...
1. Red wire of the molex connector taken from.
2. The 12AWG red pump(+) cable
3. The red wire of the grey connector

I assume the red and black wire of the molex connector is grounded to a good chassis ground.

[Ngrabau]

This is indeed very puzzling. I like to continue on some more diagnostic work if you don't mind. I have not had this happening on the v2 at all, thats why I am taking a special interest on tracking down the cause.

Are you using the wiring diagram for the 06sti on this site? Can you give me some help:

Where is ...
1. Red wire of the molex connector taken from.
2. The 12AWG red pump(+) cable
3. The red wire of the grey connector

I assume the red and black wire of the molex connector is grounded to a good chassis ground.



I will start be correcting a glaring typos that I made in the thread title and throughout this thread. This car is in fact a 2006 not a 2007.

It appears that all the dash wiring is essentially the same, but I know that it may change the diagnostic process a bit. Maybe you can change the thread title for me to reflect the correct year for other that may have similar issues.

Ok, so:

1. The red wire from the Molex connector is connected to the y/rd wire I mentioned using many times previous. (I dont know if this helps you, but its pin 6 on the blue connector B271). Its been a known good 12v source for many, many other subarus Ive working on.

2. The power to the pump goes right from the Howerton Engineering tank box located in the trunk, down the driver's side (left side) rocker panel under the carpet and out into the engine bay to the battery. I originally began my testing with the pump relay unplugged, it doesn't seem to matter if its plugged in or not.

3. The red wire from the grey connector, (The ECU connector) is spliced into pin 14 on the D137 ECU connector. The wire is grn/red.


Sorry about the model year mistake!

[Richard L]

Corrected the model year.

1. You are correct, this does not help me a great deal, I omly haver the ECU pinout section.

2. Good to know that it is connected to the battery.

3. This is also good.


Re-locate the molex red and see if it makes and difference. In fact you can connect the molex red to the battery. Th ehFS-3 has its internal (=) switch controllered by the red wire of the grey harness.

One thing puzzled me. Can you hear the HFS-3 on-borad relay clicking when this happen?

[Ngrabau]

Corrected the model year.

1. You are correct, this does not help me a great deal, I omly haver the ECU pinout section.

2. Good to know that it is connected to the battery.

3. This is also good.


Re-locate the molex red and see if it makes and difference. In fact you can connect the molex red to the battery. Th ehFS-3 has its internal (=) switch controllered by the red wire of the grey harness.

One thing puzzled me. Can you hear the HFS-3 on-board relay clicking when this happen?


Thanks for changing the title.

I'll try running the Molex red wire directly to the battery tomorrow.

The problem I'm facing currently is that I can no longer get the blower motor to work. So I can't initiate the problem anymore. With the fan off, the HSF-3 works flawlessly.

However, before I managed the break the blower fan, yes, you could hear and feel a relay clicking on the board.

Richard, get some sleep. And thanks for all the help!

[Richard L]

One last question, what is the B271 connector's function? I am off to bed now.

[Ngrabau]

One last question, what is the B271 connector's function? I am off to bed now.

Here is a list of the things that that wire brings power too:
Compass mirror
Front accessory power supply socket
Body integrated module
TCM
Rear 12 V accessory relay
Remote control mirror switch
Intercooler water spray switch
Intercooler water spray timer

I just tried running the Red Molex wire directly to the battery. No change.

What I really cannot figure out is why the blower motor relay has any authority over HFS-3 at all? Currently, power being taken directly from the battery, the grounds are bolted to the kick-panel bracket and I snipped the illumination wire is completely disconnected, (I wanted to see if it changed anything, it did not).

As soon as I unplug the blower motor relay, the system turns off! I have all the diagrams for all of these things I can simply cannot find anything that they have in common. Especially now that its hooked up directly to source voltage.

[Richard L]

This is very strange indeed. Does it make any difference if the blower is on or off?

We'll go a step further...

please let me know the voltage of test pin #5. This the injector (+), same as the red wire of grey harness. This is the main supply to the H3's system relay. It will be interest if it it drops out when the blower relay is pulled out.

[Richard L]

I may have mis-read you posts.

Its the gauge that turns off and not the system? Ground the purple wire will stop any noise getting into the controller.

[Ngrabau]

This is very strange indeed. Does it make any difference if the blower is on or off?

We'll go a step further...

please let me know the voltage of test pin #5. This the injector (+), same as the red wire of grey harness. This is the main supply to the H3's system relay. It will be interest if it it drops out when the blower relay is pulled out.

Power drops out when I pull the relay. I sits at about 1.5v with the relay removed.

[Ngrabau]

I may have mis-read you posts.

Its the gauge that turns off and not the system? Ground the purple wire will stop any noise getting into the controller.


I don't think you mis-read anything, its just that the situation slightly changed once the blower motor stopped working. Now that I can't recreate the original issue, I'm trying to chase it in a different direction.

HOWEVER. . . With the help of a friend who works here, we managed to solve one of my problems.

On the D137 ECU connector, pin 14 is red/green. . . BUT so is pin 13. And pin 13 is what controls the blower fan!

This issue was completely my fault as the installer.

The blower relay no longer has any authority over the HFS-3 unit.

Now, I just need to figure out what I shorted out to make the blower fan not work.

Richard, as always you were an incredible help. Its not often that people offer such stellar customer service. I hope that you didn't lose any sleep last night over this!

[Richard L]

This is a good news, had me pulling my hairs out. At least I was homing into the cause.

Thanks for the update. Good luck with the fan relay. The red wire of the grey connector only draws ~30mA. It shouldn't damage the ECU.

[Ngrabau]

There was most certainly a sign of relief over here too. Sorry for causing some grey hairs. I really appreciate all your help.

Now I'm just waiting for a new HVAC controller. Apparently that got shorted during my testing. I just can't win these days.

Cheers

Nick