HVAC blower intermittently does not work. Solution: wiring is faulty

[bond_007]

Having owned the car for two years, it seems like about once a year, the HVAC blower would randomly (near the beginning of the hot season) just not work. The panel would change status but the blower wouldn't start at all. A restart or two later and somehow, it would. This was a once a year occurrence. This summer, it happened twice in a row, so I investigated. Based on other information I had seen on the issue, I started at the blower, thinking the control module might be at fault.

Instead, I find a rather obvious problem of the wiring to be nice and crispy. See attached photo. Wiggling the crispy wiring got the blower started again.

A suggestion for this situation I found is to solder a pigtail and a higher capacity (60A) connector. I think I am going to see if I can get replacement terminals for the stock connector for a few bucks, extend the wires after removing the bad section and hope that repair will last longer than the OEM wiring.

Any thoughts?

[Beemdog]

In most situations the heat is generated by the contact resistance, so for whatever reason that connector was making poor contact. If you clean it up and properly replace the electrical connector(s), the resistance should be near zero and the heating will go away. If the corrosion is evident on both sides of the connection, changing both the male and female wire connectors would be a good idea. Increasing the current rating of that connector shouldn't be required unless there is a widespread problem indicating a design issue.

I would run the blower for a few minutes at various speeds after the repair and check that wire for abnormal heating.

An other source of heat can be from blower wire connections to large power resistors used to reduce the voltage to the blower motor, and thereby reduce the fan speed at lower settings. Wires connected directly to voltage-dropping power resistors (generally these are white ceramic packages) will have heat conducted into them from the resistor itself.

[bond_007]

Thanks.

This seems to point to mine not being the only case of this mode of failure:
http://www.e90post.com/forums/showpo...1&postcount=18

The male (spade type connection) is part of the blower fan speed regulator, so changing that would be a major ordeal. The spades looks clean on all the contacts of the blower regulator.

The plug housing is a little melted, I have a part number I was hoping would lead me to the correct replacement part number for the female contacts but it will not look up in RealOEM. I'll run that part number by the dealer tomorrow and see if they can obtain the plug and pins.

[bond_007]

Yet another link found with an instance of this mode of failure but this version has the elusive part numbers for the connector and pins!

On the connector:
61 13 6 925 190-02

Part numbers found:
Harness housing: 61136925196
Large gauge connector: 61138377732
Small gauge connector: 61138377730

[BzsBimmer]

Originally Posted by bond_007

Yet another link found with an instance of this mode of failure but this version has the elusive part numbers for the connector and pins!

On the connector:
61 13 6 925 190-02

Part numbers found:
Harness housing: 61136925196
Large gauge connector: 61138377732
Small gauge connector: 61138377730

If I could high 5 you, I would!
I've been searching all over for these PN's.

[jdamore]

I had the same issue but I found that the sound insulation that rubs up against the wire was wet/moist. I'm not sure if the moisture was causing a short or if it caused corrosion but, I am almost positive it was the root of the issue, in my case.

I've seen a car burn down from this!

[Shaun135i]

Very interesting topic we have here! I have a 09 135i with the same crispy burnt wires and issues!

[tallnelyt]

I am almost positive it was the root of the issue

[Chewbaccam]

I thought my blower motor went out as well- this happened to me last year. I took it to my mechanic and he said he had done a few replacements similar to this. He said the original wiring used to power and run the motor couldn't handle the voltage and that caused the blowout. BMW evidently updated the wiring kits used to support the blower motors as well. I also found evidence of water damage on the backside of my glove box panel, so I don't know what is the real cause of it was. Either way, I was happy to have my warranty cover it and they just went ahead and replaced the entire wiring and blower motor.

[Shaun135i]

Originally Posted by Chewbaccam

I thought my blower motor went out as well- this happened to me last year. I took it to my mechanic and he said he had done a few replacements similar to this. He said the original wiring used to power and run the motor couldn't handle the voltage and that caused the blowout. BMW evidently updated the wiring kits used to support the blower motors as well. I also found evidence of water damage on the backside of my glove box panel, so I don't know what is the real cause of it was. Either way, I was happy to have my warranty cover it and they just went ahead and replaced the entire wiring and blower motor.

This is what mine looked like since for some reason it will not allow me to post pics here is a link to the pics I took! https://www.icloud.com/sharedalbum/#B0N5jEMpoG0kqHS

[jdamore]

Yeah.. attached my pictures. Wires looked like the OPs.

I HIGHLY suggest everyone check this connection. It happened on my 07 335 and on my 08 M3.

[Shaun135i]

Originally Posted by jdamore

Yeah.. attached my pictures. Wires looked like the OPs.

I HIGHLY suggest everyone check this connection. It happened on my 07 335 and on my 08 M3.

This really should have been a BMW recall not something we have to hunt for before our cars catch fire!

[BzsBimmer]

I wish I saved mine. My unit looked a lot worse than jdamore's. My wire connector melted to the plastic and the connector would not free itself to even try to repair things.

I ran all new wiring to new connectors. I left a loop in place so water or moisture couldn't leak on to the unit.

[Chewbaccam]

All these photos are all too familiar. Mine looked exactly like these, from the frayed wiring to the burnt out connectors. Guess there weren't enough people that complained about it. I'd suggest if you have a warranty, it may be worth checking out to see if you need a replacement so you don't have to foot the cost. All you have to do is remove the lower glove box panel and do a visual check with the help of a flashlight.

[jdamore]

Originally Posted by Shaun135i

This really should have been a BMW recall not something we have to hunt for before our cars catch fire!

Personally, I don't see this as safety issue. If this was happening to the wires entering the tail lights, it would be a different story.

So, is this a common issue people should look out for when purchasing a e9x? We'll have to see how many report in.

Bottomline: If your blower stops working, keep the HVAC off and fix it immediately.

[Shaun135i]

Originally Posted by jdamore

Personally, I don't see this as safety issue. If this was happening to the wires entering the tail lights, it would be a different story.

So, is this a common issue people should look out for when purchasing a e9x? We'll have to see how many report in.

Bottomline: If your blower stops working, keep the HVAC off and fix it immediately.

Or if your car catches fire and it's a total loss? Any burning of electrical going to anything is not normal and it's only a "common issue" because of the internet you mean to tell me you think it's fine that wires burn up and cause risk of fire and it's the buyers responsibility to know where and what to look for? Let alone taking it upon themselves to find and point out the melted and burnt faulty wires before it causes more damage and maybe a fire? Not everyone goes on forums, not everyone uses the Internet, and not everyone is adapt enough to diagnoses or find this to be a "common BMW normal FIRE HAZARD"

[AdonM3]

Originally Posted by jdamore

Yeah.. attached my pictures. Wires looked like the OPs.

I HIGHLY suggest everyone check this connection. It happened on my 07 335 and on my 08 M3.

I am having the same issue, where the HVAC unit located?

[Theodore]

Remove the plastic panel under the dash on the passenger side (3 or 4 screws along the edge nearest the passenger seat and then pull the panel towards you to remove the panel). The wiring and blower motor resistor are easily accessible and located just about the middle of the area where you removed the plastic panel.

[AdonM3]

Originally Posted by Theodore

Remove the plastic panel under the dash on the passenger side (3 or 4 screws along the edge nearest the passenger seat and then pull the panel towards you to remove the panel). The wiring and blower motor resistor are easily accessible and located just about the middle of the area where you removed the plastic panel.

Thank you, appreciate the help.

[redpriest]

Had this same issue.

[Matt335is]

Originally Posted by bond_007

Yet another link found with an instance of this mode of failure but this version has the elusive part numbers for the connector and pins!

On the connector:
61 13 6 925 190-02

Part numbers found:
Harness housing: 61136925196
Large gauge connector: 61138377732
Small gauge connector: 61138377730

Bro you do not even know how much you saved my life. My wires were fucked to where you could actually see a blue flame. I have been searching everywhere for a solution and I am happy I stumbled upon this. Thanks bond and thank you to everyone else in this thread. Literally just saved thousands of $$!

[bond_007]

I have not had any further issues with my blower since it was repaired. Car has 130k on it now. Glad that this find has been of assistance to others.