406 Heater blower experts needed....

[bushtor]

Hi,

My 2004 406 (90HP HDI station wagon) heater blower suddenly refused to start. The 40A amp fuse is ok and there is 12V in and out of it. According to the cable diagram there is a thick grey wire from the 40A fuse to a connector near the blower where it continues as a red wire.

Take a look at my blower wiring harness here: http://www.kuntigi.net/download/Blower.jpg

There are thick grey wires in the connectors at the red and green arrows. But both of these are dead as of 12V supply.

Which cable at the image is supposed to supply 12V from the 40A fuse?

Thanks a LOT if anyone can share their experiences on the blower circuitry :-)

regards Tor

[lozz]

the one in the photo, with the red arrow,
the whiteish coloured wire is the one you need to look at -it starts from the ign barrel then goes into the fuse box,
mine as done the same thing but ive just looped in a 12v feed as iknow the problem is within the ign barrel,

check the wires behind the ign barrel the problem may be there ,


regards lozz

[bushtor]

Hi and thanks for the reply :-)

However according to the wiring diagram, the 12V supply passes first the ignition barrel, then to the 40A fuse. I have 12V voltage at the fuse so the ignition barrel must be good. Don't you agree?

Do you know where the wire from the 40A fuse goes before it connects to the blower control module?

If the circuit diagram isn't correct, then it can be the ign barrel. Circuit dia says: Battery - ign barrel - 40A fuse - blower control module - blower motor.

Thanks again for comments (and references to the picture, if necessary)

regards Tor

[jasper5]

Have you checked the heater control module behind the centre console?
Have you taken out the motor to see if it works?
Did you know the engine needs to be running for the heater to work?

There is loads of info on the heater which can be found using the search facility.

[bushtor]

There are thick red wires which are the main 12V supply to the blower control module. As long as there is no voltage in these wires the blower cannot work.

I need to get this supply voltage up first. If the blower doesn't run with supply voltage to the control module I can start checking the module and the blower motor itself.

Now I'm just curious to know which wire path or connectors there are between the 40A fuse and the control module.

regards Tor

[lozz]

try putting a fused link feed to the live wire which is shown on the your picture with the Red Arrow,
if then your blower bursts into life -the problem will be down to your ign switch,


Did the blower do anystrange things before it went into retirement ie, run slower then speed up on its own sort of thing?

[bushtor]

OK I will feed the blower via a fused link to the grey wire at the red arrow connector.

There was no strange behaviour as of the blower before it fell asleep.

Can anyone confirm that my wiring diagram is wrong when it displays the ignition switch in front of the 40A switch and not behind it? (Current flowing from the battery to the blower, that is)

regards Tor

[bushtor]

I tried to inject 12V to the grey thick wire at the 'red arrow' connector. All I heard was a tiny click from a small relay somewhere. The blower didn't turn.
Just to confirm what I already knew I unscrewed the blower motor and tested it. It turned nicely from 12V direct :-)

I still want to know about the origin of the grey thick wire at the 'red arrow' connector. The other connector at the red arrow has violet and white thick grey wires, and I saw such wires leading into a thin vertical plastic junction box just beside the battery's minus pole. However there was no grey wire in that harness.

My Haynes 406 repair book states clearly that the 40A blower fuse is connected *after* the ignition switch, and I have +12V at both studs of the fuse. This means that the ignition switch must be good. However there is no voltage in the thick grey wire at the red arrow connector, and I really want to know where that wire comes from.

Any suggestions...?

Thanks for all help and comments. This is really a great forum :-)

Tor

[jasper5]

Have you checked that you have power to and from the control module?

[Doggy]

Check the diagrams here, usually much better than Haynes.

[poddack]

I had this problem a couple of years ago, turned out to be a burned out connection to the blower motor. Now it's happening again, this time the display to my aircon unit is blank unit i wiggle my ignition key then it comes on, looks like the ignition swtich.

[bushtor]

Hi again,

I read from the last post here that the control module 12V supply is only live when the engine is running. I thought it was live when the ignition was on, thoutght I've normally heard the blower run when when the engine was stopped too... Anyway there is 12V to the control module and further to the blower motor when my engine is running. The heater control module's black earth wire is earthed BUT the black wire from the blower motor to the control module is at 12V. Hence the problem is at the control module (it is supposed to PWM the motor's black wire to earth with duty cycle according to the blower speed setting).

How do I rip out that heater control module? In my Haynes book (406 ..2002) this module is located together with the blower motor. In my car (2004) it is squeezed between the center console back and the wall (beside and separate from the blower motor). Seems to be impossible to get out. Anybody knowing how to trick the control module oout so I can check its power transistors...?

Thanks again for tips

Tor

[jasper5]

To remove the control module...
Firstly remove the felt tray under the heater motor.
Look to your right and you will find the heater control module wiring behind the centre console, there is a very small self tapper with a very small bolt head on it holding the module in, unscrew this, remove the wiring connectors and pull the module downwards NOTE * It's about 4 inches long or more.
You do not need to remove the centre console.

With the engine running as I said earlier, and the heater fan switch on full, you should have power to each side of the module at the thick wires. (wires connected to module).

Power at the right hand thick wires but not at the left side thick wires indicates a broken module.

A new module costs about £56.

I've changed a few of these now on post 2001 cars.

[bushtor]

Hi Jasper5

As I said I was wrong on assuming that the blower had 12V supply when the engine was stopped. Once I tested with the engine running the situation was as described in the above post.

Thanks for the info on control module removal, First I did not bow deep enough to see the small screw. I unsoldered the power transistor N344AB and it was open. Will purchase a new one and I assume that everything will work by then :-)

Thanks to all for the help :-)

Tor

[jasper5]

You're welcome, hopefully all will be well soon