You can pull your relays under the hood and see if you jsut have a frozen relay. If so you can swap them with your heated windscreen relays until you pick up a replacement.

 

Hi,

Could this be the same issue on your P38?

viewtopic.php?f=3&t=43460

Fan of HVAC left or right is at full power and does not stop.
Pull RL 6 or RL 7 may stop the full speed fan, relays under the bonnet close to battery (fusebox)

Regards,

Werner

 

Thanks for the link. Good read.

I'm going to try the relays tomorrow. I hope that solves the issue. If I have to replace the motor this could be like an $800 bill as I'm sure the whole dash needs to be removed. Yuck.

 

jeez... where to start?

The system will not reset by disconnecting the battery.
The HeVAC system checks itself out every time you start the car.
If there's a problem, the book light comes on.
If there's not a problem, no book light.

Pulling the relays will stop the fans.
It won't solve your problem, and now you'll have no heat, but it WILL stop the fans.
More to the point, you will have learned absolutely nothing by removing those relays.
You know what? You could disconnect the battery, that would also stop the fans.
And you still wouldn't know what was causing the problem.

If your left footwell gets wet when it rains, there's water coming in through the air inlet.
Are you missing the cover under the hood? How about the little gasket around the edge of it? Is the pollen filter all wet, too?
So water comes in there, runs down through the blower motor (which, remarkably, is now acting funny) and onto the floor.

The drainage holes (tubes?) under the truck drain the condensate from the AC; a natural occurrence of an operating air conditioner is that it dehumidifies the air. that moisture has to go somewhere. If those drain tubes are clogged, you'll notice moisture on the transmission tunnel side of the footwell. Which side of the footwell is wet? If it's the outside, water is probably coming down through the fresh air intake.

The only impact relay 7 could have would be if it was "stuck" "off".
If relay 7 is stuck OFF, the motor would not work at all. This is obviously NOT the case.

If it was stuck ON, AND you had a short (described below) to your blower control line, the blower would run even with the engine off.
If it was stuck ON, and there was no short (described below), you'd never notice, since as soon as the BeCM is wakened by the key turning, that relay clicks on.
If relay 7 IS stuck ON, and you swap it with the heated windscreen relay, your heated windscreen will now ALWAYS BE ON.
Swapping with relay 5 would energize both sides of the windscreen heater. Relay 4 stuck on would only turn on the right side.
This is less than ideal.

Do you have the Electrical Manual?
Don't go switching things around without understanding what you're doing.
Would you go re-arrange the wires in the electrical panel in your house without understanding that?
I hope not.

relay 7 gets a continuous +12V feed from the battery.
The BECM gives it a ground, which energizes the relay, sending +12V to the blower.
The blower gets a variable voltage (between 0v & almost 12v) from the HeVAC unit to set blower speed.
0v from HeVAC would run fan at max speed.

Lets say some water got in there.
perhaps causing a short between anything metal and the HeVAC signal line.
Now, no matter what the HeVAC unit says, the motor sees +12V from the relay as usual, and 0V (ground) on it's variable voltage input.
The motor goes to full blast.

Remove the panel beneath the steering wheel, 4 or 5 screws with plastic covers.
detach the hose for the lap vent.
the blower motor is right there, to the left side.
4 screws hold it in.
the YELLOW jacketed wires MUST NOT BE DAMAGED.
These are the airbag lines.
Mess this up, and the steering wheel airbag will explode in your face.
You'll have to wrestle with the cable troughs a bit to get the motor out.

Before you tear out the motor, figure out why water is coming in.
fix that.
check to see if things are wet.
if they are, dry them off.

see if that fixes it.
give us an update, and in the name of everything holy, do NOT go to the dealer!!!

 

Hi had this problem yesterday when i changed out a dud heater matrix temp sensor and went to clear faults i also got a lefthand blower overrun fault couldn't clear it so looked at the livefeed on the faultmate and sure enough it was only 6%, replaced relay with another same thing ,got a new one and all ok. So save yourself some money go buy half a dozen relays replace Rl 6 and 7 the one closest to front of car RL7 :thumb: is the main colprid u should see a hot burn mark in socket and the relay will be brown at the terminial end of the yellow plastic cover.