I was finding out why my car would get to 100*C+ on the highway in a little bit of stop-n-go traffic. Yesterday, I was on my way to In-n-Out here in Northridge CA on the 118E freeway. I used the AC on the freeway and it normally wouldn't shoot up to 100*C.... Pulled over to check it out and came down to find that my AUX fan was dead.

This morning I checked the AUX fan to see if it works on a straight connection and it worked! Thank goodness....but I did some continuity tests and I think it's the resistor (is that what it's called? Picture 1).

Leaves must have collected and kept moisture in that compartment where the fusebox and the break reservoir is...The one reason I try to avoid leaves in this part is because of picture 2...rust!

Now I'm in the process of finding a new one...Anyone know what that part# is? Is it a resistor?

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It's not the years, it's the mileage.

what part of the engine bay is this picture taken...

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Current Garage
2008 Mercedes GL320 CDI 188k mi Repair/Work in progress
1994 S350 160k mi Garage Queen & prepping for repairs
2005 E320 CDI 203k mi Healthy & Daily Driver
1994 S350 357k mi Retried as parts car
1984 300TD 214k mi Blown OM617 Poss OM603 Swap??

Sold
1987 300SDL 200K+
1994 S320 181K mi
2008 E320 Bluetec 127k mi
1999 S420 130K mi
1980 240D 360k mi
15+ Others that has come, stay and gone

GONE, BUT NOT FORGOTTEN
1995 E320 SE 220k mi
1984 300SD 350k mi

First picture is of the area down under the brake booster, second pic is under the battery tray.

Its normal for leaves to get in there......I clean mine every once in a while to prevent buildup.

Thats not the aux fan resistor, its the interior blower resistor. The aux fan just has a relay in two locations (A/C system, and engine)...its only modes are OFF/ON....no resistor required.

Your temp issues may be Aux fan related, but I'd also make sure the radiator is not plugged up with dirt and that the thermostat is opening properly.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

In the process of doing a flush of the coolant system and cleaning of the radiator. It's going to get hot here in LA and I'd like the peace of mind knowing that the car doesn't get too hot.

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It's not the years, it's the mileage.