Radiator fans
 

When should the auxillary radiator fans come on in my 1999 ML320? I asked the service department at my dealer and was told they cycle with temperature. I ask if they came on with the air conditioner like in my 190E and was told no. Is this true or were they putting me on. The temp even on hot days with the AC on is just above 80 c. An independant mechanic told me the fans should come on with the AC. What is true? Also I have been reading about a wiring harness modification on the AC fan fuse. Can anyone tell me more about this modification and why it is necessary?

Any help would be appreciated,

Cliff

1999 ML320

If you have the original wiring harness and fuse you need the upgraded versions. The fans should run when the air is on. If you are the original owner of your truck you might be able to get them to goodwill the upgrade. See this thread http://www.peachparts.com/shopforum/ml-gl-g-wagen-r-class-unimog-sprinter/91035-aux-fans-blowing-fuse-44-ml-series.html Good luck ;)

This is not true. I can't tell you if they were "putting you on", but the statement is false. The fans come on with the AC high pressure switch, so not "automatically" with the AC, but under certain circumstances they will, even if the engine isn't very hot.

Find and check fuse 44 in the main fusebox and see if it's blown. If it is, the different harness for the aux fans likely needs to be installed. Read the link in azinns post, should explain everything pretty well.

Gilly

Thanks for your help. I do have a question, one end of the green whire goes to the fuse block, where does the other wire go. At the fan connector I have two green wires and two brown wires. Will I need a tool to remove the pin from the connector. Gilly indicated the connector comes apart to replace the pin or socket. Is there a trick to getting it apart?

Next question can anyone tell me what the AC pressures should be, Low side and High side?

Thanks
Cliff

Have you purchased your new harness yet?

Ron,
I have not purchased the new harness yet. I am still researching to see If I can do the job myself. I have not checked the price of the harness or what it looks like. From all the information so far has me believeing it is just one wire with sockets on both ends.

Cliff,

I asked that question because I’m not certain I understood yours.

The new harness had either one or two wires that you route into the fusebox. One for sure is green. You remove the old green wire from ML/B connector and connect the new one in its place. They do make a special tool to easily remove the wires from the connectors but I don’t have one. I used an eyeglasses screwdriver to get mine out.

If there is another wire that gets routed into the fusebox maybe it was a ground. If you get a harness post a photo and hopefully it will refresh may recollection or someone else will have the answer. I remember it was not hard to tell what was what once I finally identified ML/B.

As far as the plug connector at the fans you get a new connector with the wires and all that you just plug in after you unplug the old one, nothing to that.

Edited:

If there was another wire that gets routed into the fusebox besides the green one it might go to ML/B connector too. That means you will remove both of the existing wires from ML/B