I think i have an electrical short, how do i find it?

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ID Status Date Year Make Model Transmission Type A/C Controls Public/Private
#14792 Closed 2000 BMW 323i public

I have a 2000 BMW 323i 4 dr sedan. Just recently the # 28 fuse in the glove compartment has been blowing almost every time I have started the car. This causes the climalte control system to not work at all… the A/C, the heater, the blower, defroster, etc… I have totally removed and disconnected the climate control module and it still blows. There has been two times in the last couple of days while I have been trying to figure out the answer, that the system has worked for a short time, and then the fuse blows again. I thought that my moving wires around a little maybe caused a possible bare wire to not short out or something, so I think I’m looking for a short. I’m just not sure where to begin looking. Or. maybe dit is something else that is going on. I also cannot find any useable wiring diagrams that might help me. Any suggestions?
Sparky

So far I have found no common cause. The best I can tell you at this point is to look for an issue on a green/yellow wire.  According to the diagram, fuse 28 feeds the rear window defroster relay, the HVAC control panel, the dual function switch recirculated air/rear window defogger and the temperature switch. See attached diagram.

Thanks for the info, that helps. However, I do not see the ‘attached diagram’ mentioned. Did I miss it somehow?
Thanks.
Sparky

Hopefully it uploaded this time.

Yes, it did upload. Thank you.
Just a follow-up. I have removed the rear window defrost relay, the heating and a/c control module, the blower final stage resistor… which I was told could possibly be the problem… and the a/c compressor relay. The fuse still blows each time I start the car. I realize the possibility that there could be a short between the fuse and the relays, etc. I have inspected the wiring as close as I can and find no worn areas. I’m now looking for the location of the “Dual function switch recirculated air/rear window defogger”, and the “Temperature switch” as shown on the diagram that you had downloaded. This morning I replaced the fuse and started the car and the a/c/heater, etc, and all worked great… I started the car and turned off the ignition and started it again several times… I had left the fuse box in the glove compartment open and undisturbed thinking that moving it may cause a short. It worked well during my driving about 40 miles… and then all of a sudden the fuse blew and it quit working again. Wondering if the cool gtemperature in the morning helped it to work until it got warmed up… don’t know.
I’m quite frustrated, and if you have any other ideas, they would be appreciated.
Thank you for your help.
Keith Hammond
Sparky

It is a long shot but you may want to find the water valve assembly and the auxiliary water pump. Disconnect one at a time to see if the problem goes away.

Thank you for info… I did try disconnecting the water valve assembly with no luck…. same thing. I have not been able to locate an auxiliary water pump though. Is there one on this car? Anyway, i put in a new fuse this morning and started the car. All is working again, so it seems that the ambient temperature may have something to do with it as it seems to work when it is cooler as it is this morning. Or maybe just the car itself being cooler. Any other thoughts?

Sorry to be such a pain, and I do thank you for your help.

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