Electric radiator fan problem
 

I have a 1995 MBZ E 320 wagon that has a problem with the electric cooling fans, in front of the radiator. First one fan stopped working. After a few weeks, the second fan stopped as well. I ordered a replacement fan, which I have not installed but before I order a second fan,I wanted to ask if there could possibly be an electrical problem like a relay or other device? Please advise when you can. Thank you.:confused:

Hello - I've attached a DIY tech article from our site that I hope you'll find helpful in troubleshooting and hopefully resolving your radiator fan problem. If you have any other questions, feel free to post a Comment just below the article and we'll do our best to give you some more details.

Mercedes-Benz W124 Cooling Fan and Shroud Removal | 1986-1995 E-Class | Pelican Parts DIY Maintenance Article


-Dmitry

Dmiywit:
When all else fails, read the OPs statements.

There is one very quick and dirty test for your fans, remove the connector from the blue two pin connector on the thermostat housing - the fans should run full speed (this is dependant on the fuse, relay and wire being good).

The two relays that run the fans are in the fuse box near the master cylinder - the one a bit rear to the car and is closed with screws. There should be two relays with fuses on top, one relay is blue with a 15A fuse and one is green with a 30A fuse.

There is also a resistor behind the driver headlight near the A/C reciever drier. That resistor is the for running the fans slow. At full speed the resistor is bypassed.

To test it all you need is a test lamp, start the engine and see if you have full battery power at the "out" leg of the resistor, the bypass is simply a wire from the high speed relay bolted there. - so at full tilt the power is supplied there bypassing the resistor. To test low speed test before the resistor.

tracing it down you should be seeing this same voltage at the 2 pin connector which is nested in a spring steel housing next to the radiator. The ground for this is on the ABS pump bracket - its usually ok unless you live in a salty winter state.

In my car the resistor had toasted both hi and low speed wires rendering me with no electric cooling fans, the resistor is available from this site's store and is quite easy to swap out (remove headlamp to get it to it rather than from the top)

I found my fans (95 E320) had bugs, straw and dirt packed under the air vents behind the fan hub which had become trapped against the condenser grid..I blew out with a compressor but still, there was a lot of debris in there when I removed them. I whacked the fan hub at times from the front when they would stall and they took off working again, reliably.

Another tip is that the article says you must remove the radiator and pull the fan assy from the rear, if I recall correctly. I took them out from the front after removing the plastic rivet pins that hold the plastic cover. Then was able to undo the nuts and pull the fans out the front, with the little vertical crossbrace removed also, of course..

Now to successfully RE install the fans and he condenser coils I may indeed need to remove the radiator and do it from inside/ie behind, as the book says.

I pulled the fans from the front because I needed to do sheet metal straightening after a wreck that bent the frame, what a mess..All coming together again now.

Another note about the cooling fans is that the high and low speed relays are often confused and have the wrong rated fuse. In my car I replaced the 15 amp fuse on the relay which was blown and immediately the fans worked great, but then fuse D (believe it was) began melting out. And I heard this was typical. It does not blow but overheats and melts out the fuse block plastic, stinks like a burning tire! I shimmed it with a screw and then finally soldiered leads into the fuse block and added a blade fuse with marine grade hardware for ten bucks from England marine, its worked flawlessly and does not even get warm. Very important year round to have the AC and these electric fans working continually. I find the climate system has functions integral with the engine operation year round and prevents overheating and regulates engine temp to the proper limits. I suspect a lot of the head gasket issues with these cars are due to bad electric cooling fan systems resulting from failure to replace the cooling fan fuses and keep the AC system working, then one gets marginal overheating that stresses the gasket and the large aluminum head expands too much for the gasket seals to survive.

Damn! What a pain. Funny you mentioned A/C, as that does not work either! I did replace the heater valve a few years back, as the AC did not work at that time either! In my case, one fan stopped working. A couple of weeks later the second fan stopped as well. The cold air from the A/C stopped before to the second fan quit?? I checked the fuses that you mentioned right away and they were in tact? It must be the resistor that you mentioned. Do you happen to have a name/part number for the resistor in question? I am from the US but currently in Chile and trying to get an answer here is like pulling teeth. These geeks wanted 1,200.00 USD for a replacement fan!!! My email is d.kropelnicki@startmail.com Your help is sincerely appreciated. Many, Thanks

the part number for the resistor is

000-158-32-45

and is about 25 dollars on this site's shop for a good genuine quality part. First make sure where your wiring has failed, on both positive and negative side. Dont just throw parts at it.

Electric fan(s) problem
 

Many thanks for your help with this and your advice! I have checked to fuses in the fuse box and they are OK. I will disconnect the wire from the thermostat housing and see what happens. I will get back to you and let you know what happened.

Best regards,

David