F3 provides power to the HCS (headlight cleaning system) at pin 2 of K2 (relay located in the relay tray near the fuse box, see attached pdf) AND it provides hot power to the HCS washer motors, so IF these are disconnected there is the potential for a hot short (i.e. water getting into the connector providing a path to ground, or loose wiring getting pinched or rubbed until a short occurs). So I'd start by measuring resistance to ground at pint 2 of the K2 socket; that will tell you if the HCS is causing your f3 to blow.
Max -----Original Message----- From: mercedes-boun...@okiebenz.com [mailto:mercedes-boun...@okiebenz.com] On Behalf Of Wonko the Sane Sent: Sunday, September 13, 2009 8:32 PM To: Mercedes Discussion List Subject: [MBZ] OK, experts, what do I try next? My '86 300E is blowing the #3 fuse. According to the fuse panel lid, #3 is in charge of parking / tail light right, headlamp cleaning unit, illumination: license plate, instrument, control elements [not sure that last one means]. I have tried the following -- always resulting in a blown fuse when I turn the headlights. - unplug right rear bulb cluster - remove both license plate bulbs - unplug instrument cluster Each time, the fuse still blows. I can't find any way to unplug the headlight wipers, other than to cut what I think are the wires (NOT going to go there, even though the wipers don't work). Any suggestions? I have awakened about 3 AM several times over the past few weeks trying to troubleshoot this. I am (was) an electronics technician, so I should be able to track down a short -- but can't seem to. I am pretty close to disconnecting ground from the battery and using an ohmmeter to see if something that should be "hot" is actually ground, but I suspect unexpected ground would feed back through the entire wiring harness. -- DPAD. The young officer thought it very odd that his captain seemed to trust and confide in his chiefs more than his wardroom, but mustang officers had their own ways. -- Tom Clancy, Clear and Present Danger. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://okiebenz.com/pipermail/mercedes_okiebenz.com/attachments/2009091 3/a1e44cad/attachment.html> _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com -------------- next part -------------- A non-text attachment was scrubbed... Name: 124 relay_control locations.pdf Type: application/octet-stream Size: 25941 bytes Desc: 124 relay_control locations.pdf URL: <http://okiebenz.com/pipermail/mercedes_okiebenz.com/attachments/20090914/6a3ecb25/attachment.obj> _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
