ml 430 aux cooling fans - PeachParts Mercedes-Benz Forum

texasdanml430 · #1 03-08-2004, 05:31 PM

they never seem to come on. how hot does she have to get? thought they should kick on when the a/c is on. if a fuse was blown, wouldnt it trip a check engine light? do i need the wiring harnes? its a 2000 model.

Ali Al-Chalabi · #2 03-08-2004, 05:49 PM

No wiring harness issue on this vehicle.

Fuse blown will NOT set the check engine light.

Fans come on with A/C at a certain pressure or high coolant temp.

Not sure of the cut-in temps and A/C pressures on the ML, but on my C280, low speed cut in is 100C coolant temp or 16 bars A/C refrigerant pressure and high speed cut in is 115C coolant temp or 20 bars A/C refrigerent pressure.

texasdanml430 · #3 03-08-2004, 06:15 PM

thanks Ali; thought the thing wasnt supposed to get much over 80 deg C. thats the thermostat open temp anyway, right?
by the way, what is a 'bar'? how many psi's is a bar?
thanks again

PHAEDRUS242 · #4 03-08-2004, 06:54 PM

check fuse 44-these things blow all the time!! there is an updated wiring harness for the aux fans. almost every ML that comes into my shop has had this modification performed at one point or another. it's a simple repair for the mechanically inclined, or it will run you between 1.5 and 2.0 hours labor at a shop. also, a "bar" is around 14.3 psi...

Gilly · #5 03-08-2004, 09:25 PM

Check the serial number of the truck. If it is lower than A145272, it needs an updated harness installed for the aux fan. Here is the service bulletin number: T-B-83.30/62 dated Sept 3, 2002.

Gilly

Ali Al-Chalabi · #6 03-09-2004, 09:53 AM

Thermostat should start to open at 87C and will not be fully open until 102C. 1 bar is equal to 14 psi. Engine is designed to be above 80C all the time.

Sorry, I stand corrected on the wiring, I did not realize there was an updated harness for the fan.

texasdanml430 · #7 03-09-2004, 11:01 AM

wow. this is what i call SUPPORT! very impressive to an MB newbie diy guy. thanks, guys, i'm all over it.

Gilly · #8 03-09-2004, 09:35 PM

I should also mention Phaedrus242 is correct about checking fuse 44. Replacing the fuse will make it work again, but you should get the harness replacement job done, this is the "real" fix for the problem. If it were hot out and I needed the fans to run, I'd go ahead and replace the fuse, just to cool things down, but try to get it "really" fixed by doing the harness job. I believe one quick way to see if the fuse is possibly blown, without even opening the hood, is I believe the rear window washer pump also is inop with a blown 44 fuse.

Gilly

vince · #9 03-10-2004, 09:24 AM

Not to be a "smart a**", but 1 bar = 14.50377 PSI.

Q · #10 03-10-2004, 09:55 AM

Our 2000 ML320 has had the updated wiring harness done.

texasdanml430 · #11 03-10-2004, 11:11 AM

well, fuse 44 was blown, but the rear windshield washer was still working. i just showed how cool it is to my wife recently. anyway, replaced the fuse and will run the a/c and watch for it to blow again. guess i'll have to make a trip to the dealer, 45 mins away for the new wiring. anybody know what this will cost? i am still under warranty i think. i am capable of replacing this myself.
thanks all

Gilly · #12 03-10-2004, 06:38 PM

Not sure on the price. The warranty should cover it. If all else fails, you should be able to handle it yourself. The part number I have (may be superceded part) is 163-540-00-35. also need a 40 amp mini-fuse, MB number for it is 910153-000000, but you can find that locally too I'm sure. You'll need to get a copy of the bulletin for directions.

Gilly

PHAEDRUS242 · #13 03-10-2004, 07:24 PM

that part number is current, warranty time is 1.5 hrs and it is covered by MB factory, starmark and MB ELW warranties (the one you pay for from the MB dealers). actual job is a piece of cake if for some reason you are no longer under warranty.