On the E60, changing the blower motor/squirrelcage is like doing spinal surgery from the front. Lots of stuff has to come out to reach it from the console area.

So, if you're in there, replace the controller ("resistor") attached to the blower, and be right the first time.

Like the thermostat on the coolant pump, you only want to go in there once.

 

I'm in an uncommon situation where I'm selling the car, so a quick fix will do. My old blower motor has metal cages, and is rusty but i greased it two years ago when i was in there last for an arced black (loose) contact from the power supply on the resistor module.

I can't fix everything, and now I'm trying to maximize profit. If the cheapest fix means a failed free fix and a week or two of driving around without a dash I don't mind.

 

To follow up on this. It was as I suspected. That same connection was arcing again. Some cleaning, some copper antisieze in lieu of dielectric grease, and it's working again.
The resistor appears to be encapsulated and not serviceable.

My cages are plastic... My mistake.

Proper fix: cost of the cable.

 

To follow up on this. It was as I suspected. That same connection was arcing again. Some cleaning, some copper antisieze in lieu of dielectric grease, and it's working again.
The resistor appears to be encapsulated and not serviceable.

My cages are plastic... My mistake.

Proper fix: cost of the cable.

Was this due to arcing or is the contact flaky due to the high current passing through the junction point and over heating that connection, which will get progressively worse.......?

 

Your guess is as good as mine. Maybe just oxidation causing resistive heating. In any case, the cable clearly started to melt, and the connection was pretty oxidized.

I was in here doing this same thing maybe two and a half years ago. So cleaning is not a permanent fix but buys some time.

Whatever the cause, the blower and resistor were not the problem. Switching out both wouldn't have helped in this case.

 

https://www.newtis.info/tisv2/a/en/...u/wiring-functional-info/body/heating-air-conditioning-functions/blower/uiRA6RP

Wiring diagram shows connector X13728 as well as the unlabelled 2-pin that goes to the motor itself. The wire colors match up with the car side of the harness (brown, red/blue, blue/red) in your first photo. Two large wires are actual power & ground, while the smaller one (labelled LIN_GEBL) is the data connection where the computer tells the output stage how fast to spin. Technically the black lump isn't a resistor, wiring diagram refers to it as an output stage.

Those power wires are 4mm^2, roughly 12AWG. In house wiring that'd be good for 20 amps; in your car the circuit is fused at 40 amps. There's a lot of current running thru there.

I've seen pin & socket connections get loose and resistive and hot and melty and burny in other applications, including theater lighting and pinball machines. Root cause in those dry applicatinos is usually a mechanical bad fit from repeated plug/unplug cycles. Though if there's been any water getting into your HVAC area, it could cause minor corrosion on the pin which increases resistance and it's all downhill from there. It's never going to get better until you replace stuff, which I understand isn't happening in this case.

Amazingly, Tyco admits to that part number as being a harness for our cars, but doesn't give any better information, or purchasable replacement contact numbers.
www.te.com/usa-en/product-235141-1.html

(edit) Yep, looks like it gets rusty in there. Pics 11 & 14 show it pretty well.
https://www.pelicanparts.com/techar...sistor_Replacement/66-ELEC-Blower_Motor_&_Blower_Motor_Resistor_Replacement.htm
I guess if there was enough condensation to form droplets on the wires, it'd drool down into the pin&socket connections and start causing problems.

 

Root cause in those dry applicatinos is usually a mechanical bad fit from repeated plug/unplug cycles. Though if there's been any water getting into your HVAC area, it could cause minor corrosion on the pin which increases resistance and it's all downhill from there.

Note that the motor shafts in this one and mine when I did it were rusty as hell, so I assume this environment is high humidity.

 

Cable connection was pretty loose. I squished it with some pliers... Seems to fit a bit more snug now.

When it's really hot out, max ac, I get water droplets spitting out the vents. I wonder if the drain is partially blocked and that's the underlying cause.