Where is the Aux Fan Control Located and How Does It Get Replaced - Page 2 - PeachParts Mercedes-Benz Forum

compress ignite · #16 05-14-2012, 01:34 AM

That Electronical Aux Fan controller is about a Franklin(And an 'Arf).

AND the only real problem with the original system is the AWG/MM of the Wiring.

The "resistors",archaic as they are, Last a Long time.

EDBSO · #17 05-21-2012, 03:58 PM

Thanks all.
Found by removing front headlight.

Car is home again.

Two road trips and two major $$$$ and two strandings!!!!!!!!!

The first an alternator 2,576 miles from home and stranded.

The second 2,528 miles from home and stranded by failed aux fans and control unit again major $$$$.

Are 1999 E300 Turbo Diesels only city cars and shouldn't be taken farther from home than you can afford to have them dragged back home?

scotrvmarine · #18 07-17-2012, 04:53 PM

Quote:

Originally Posted by Jeremy5848

The 1995 E300D (OM606NA, W124) has the resistor that's in your second picture; older 124s have an earlier version of the same resistor.

The 1996-97 E300D (OM606NA, W210) uses a generic "pulse module" that lives in the fuse/relay box, left side of the engine bay near the brake booster. It does not use the big resistor.

The 1998-99 E300D (OM606 Turbo, W210) uses an electronic controller for the aux fan. The electronic controller, one of two types depending on year/model, is located in essentially the same place as the old-style resistor: inside the left wheelhouse, just behind the left headlight. You get to it from inside the engine compartment. Pretend you're going to change a headlamp bulb but look just behind the headlight and ahead of the ABS pump.

Jeremy

Hello,

My first time here I am so thankful that I found this information about the Aux. Fan controll. I have a 1999 MB E300D. I have looked and looked where the above indicates, (inside the left wheelhouse, just behind the left headlight. You get to it from inside the engine compartment. Pretend you're going to change a headlamp bulb but look just behind the headlight and ahead of the ABS pump.) and I can not find the fan controller. Any chance that it is below the washer fluid jug?

EDBSO · #19 07-17-2012, 05:31 PM

Quote:

Originally Posted by scotrvmarine

Any chance that it is below the washer fluid jug?

None! The mechanic who did mine took the driver's headlight out and it was under the light, saw it from the waiting room, I did not go right up to the car to see it up close.

Hope this helps

TMAllison · #20 07-17-2012, 05:47 PM

You can test the aux fan operation using the CCU; with key in pos #2, hold both "auto" buttons for 10 seconds. Fans will engage full speed.

scotrvmarine · #21 07-17-2012, 05:57 PM

Great, thanks for the location information. The problem I am having is that the fans cycle up and down in speed but never go to full speed. I jumped the wires and the fan runs great. I am assuming the fan controll is the culprit.

Thanks,
Scot

TMAllison · #22 07-17-2012, 07:59 PM

The test described above should put them to full speed. If they don't hold that speed in diagnostic mode I'd suspect the controller.

Surprised you notice them being on. Mine only cycle on when its a 100-105f day and then only after exiting the freeway and entering stop and go traffic.

EDBSO · #23 07-17-2012, 10:00 PM

Quote:

Originally Posted by scotrvmarine

Great, thanks for the location information. The problem I am having is that the fans cycle up and down in speed but never go to full speed. I jumped the wires and the fan runs great. I am assuming the fan controll is the culprit.

Thanks,
Scot

That sounds normal.
What temperatures is your coolant running at?

scotrvmarine · #24 07-20-2012, 09:02 PM

The coolant temp runs around 80 unless I get in stop and go traffic. Then it has risen over 100.

I tested the clutch on the engine fan and have a new one on order. I am also going to put in a new controller for the electric fans as they barely move even when the coolant temp has climbed above 100. Hope this will solve the high temp in traffic and warm AC in traffic.

EDBSO · #25 07-20-2012, 10:15 PM

Quote:

Originally Posted by scotrvmarine

The coolant temp runs around 80 unless I get in stop and go traffic. Then it has risen over 100.

I tested the clutch on the engine fan and have a new one on order. I am also going to put in a new controller for the electric fans as they barely move even when the coolant temp has climbed above 100. Hope this will solve the high temp in traffic and warm AC in traffic.

OK Too hot. Over 100 is not good. Sounds like a good plan.

Kajtek1 · #26 08-23-2012, 04:06 PM

Quote:

Originally Posted by scotrvmarine

The coolant temp runs around 80 unless I get in stop and go traffic. Then it has risen over 100.

I tested the clutch on the engine fan and have a new one on order. I am also going to put in a new controller for the electric fans as they barely move even when the coolant temp has climbed above 100. Hope this will solve the high temp in traffic and warm AC in traffic.

If you have diesel going to 100C that means your cooling system lost its efficiency.
I have 3 years old radiator on 1998 E300DT and I drive in California with engine fan removed. At 102F outside at 70 mph the engine stays at 78-80C. Got up to 95C in city traffic, but when left idling on parking lot, it drop down to 92C with AC at full blast. The electric fans were on slow.
I am strong believer in MB coolant and read lot of replies where guys using cheaper stuff have problems with engines getting hot.

ready-ronnie · #27 09-01-2012, 09:38 AM

I just finished installing(thanks to the DIY guys) a set of used Aux. fans. They work when I use the test method with the Auto buttons. The cold air comes on when I run the air condition, but as soon as the compressor get hot it shuts down because the Aux's do not start. Now what?

smk_texas · #28 04-16-2018, 12:32 AM

Hi ,
The ac fan does not come on in my 96 e300d. My control module is faulty. I traced the wire/cable from the aux fan and noticed that goes into the fuse box. After that i can't see where/what it hooks up to and don't see a control module inside the fuse box. Any input is appreciated. Have a great day !

smk_texas