SOLVED: Aux Fan power circuit issue
 

All,

Finally took the E53 to the dealership and got a very odd diagnosis of my aux fan issues. I know when I took it in that I had power on the red/blue fan wire that runs from fuse 61 to the fan harness. They claim there is not continuity on that wire now. So it would seem I will verify what they say (which is very odd) and if true I will replace the wire.

Does anyone know the route of that wire from the fuse box and over to the fan harness? If it's a messy one, I might just wire from the + terminal in the engine bay with a 50A inline fuse to the fan terminal and put this to bed for now.

I may put a new wiring harness on the rig when I send the engine out for a full rebuild in a year or two.

Anybody played with this that can give me some guidance?

SOLUTION:
Wire actually routes (on my build as if it's a 4.8IS) from fuse 61 to Fuse 107 (on top of the fuse box) then onward to the fan plug. The red blade fuse was fine but we showed no continuity to the fan plug. Upon the suggestion of our members (especially BDC101) I checked fuse 107 and it sure was blown. The dealership refused to open up the top of the box as they claimed there was no secondary fuse (as per the BMW electrical schematic for 4.6is...which is DEFINITELY wrong on my car and seems like a few more). They were wrong. I pulled the fuse block out, opened the top case, checked for voltage across the fuse and found none. I replaced the OEM 50A (all black fuse) with one that I could see through in the future and tested. Fan fired up and has been running for a day and a half.

I hope this helps others that may be in the same boat thinking they have to pull a new wire from the fuse block to their fan plug.

maybe this'll help
 

Being a newbie, I looked into a wiring diagram that really doesn't show much, Attachment 80757
but only shows one connector between Fuse61 and the fan (X10455). It doesn't look like it runs into the DME, nor tie into any other circuit.

If I was a little more sure of my footing here, I'd run a wire directly (using a fuse tap, with its' own fuse, just in case) from the F61 to the red/blue wire near the fan connector. As a test.

Check the fuse F107 behind the glove box. Just humor me on this one. See:



https://xoutpost.com/bmw-sav-forums/...continues.html

OH for the love of all things BMW....I just messaged my Service Advisor to have the tech check F107 before I pick it back up. I copied an entire section of that posting to them as I'm sure they will say F61 only ...yada yada yada....so let's see what happens.

I thought I had read everything on this forum about this issue but I sure missed THAT ONE.

I cant tell you how much I appreciate the input!

Just make sure to report back so we know if my car was an isolated case or if there are more cars with the problem. Mine is a 2003 as well so it is possible that some cars of that year had been wired up like the 2004 and later cars without it being documented.
I hope it doesn't waste your time!

It won't be a waste of time either way. Either my fan gets fixed or not and I have to dig deeper. That being said...it would stand to reason that there are many more of these wiring diagram mismatches out there if there is one...there will be more.

SOLVED: No continuity fuse 61 to Aux fan plug
 

Well everyone, it was indeed fuse F107 that was the culprit. I replaced the fuse and the Aux Fan fired right up and I was able to control it via INPA as well.

My build date is 4/2003 so my 4.6is is another example of the wiring diagram from a FACELIFT e53 is correct and not what BMW has published.

So the wire routing is Battery >Fuse 61 (50A red blade fuse) > Fuse F107 (50A Fuse strip at F107 on top of the fuse block in the glove box) > Aux Fan plug Red/Blue wire.

I hope this helps others in the future from beating their heads against their engine blocks. LOL.

Glad you sorted it out.

Great call Bdc101! :thumbup:

Wow! That's crazy. I'm so glad it helped you find the problem. I have to admit that the others my troubleshooting thread from last year did all the heavy lifting, so kudos to all of them.