[m103] solved: constantly running aux fan
 

Just thought I should add my experience with aux fan woes. Both my fans on my 1990 300e were constantly running once I turned on the ignition. Even though the ac is not even working. I ordered coolant temp sensor and the black relais behind the fuse box. Turned out I didn't have the correct socket for the temp sensor but I replaced the relais (0015426819 in my case) and the fans are no longer running constantly. It remains to be seen wether it kicks in if the engine should start over heating. I just replaced the fan clutch and without ac too there is not much chance for that here in Norway. Anyway.

The black relays are no good. They should have given you the superceded part, which is an orange or green relay with the fuse built into the top.

I'm almost positive that you narrowly missed an underhood fire. Since the fans are wired directly to the battery, the relay itself incorporates a fuse. With the black relay, the fuse is internal and can't be replaced. My experience is that when the relay fail s closed, the fuse overheats and can burn the case.

http://www.peachparts.com/shopforum/attachments/diesel-discussion/131750d1440306806-troubleshooting-electric-fans-blackrelay.jpg

http://www.peachparts.com/shopforum/attachments/diesel-discussion/131751d1440306994-troubleshooting-electric-fans-orange.jpg

Oops! Interesting thanks! Anyway aux fans work as they should - kicks in when engine temp approaches 100.found out when I was parking for a long time in a very narrow spot and turned ignition on again right after I stopped.

Is there another part number for the orange relay?

I believe its 0015429719

Dam we should switch cars I can't get mine to even turn on lol

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