[PNWn55]

Hey everyone, if this is in the wrong section sorry I have an electrical question. My car died today while driving and after some digging fuse 37 had blown. Can someone tell me what this fuse protects and where to look for troubleshooting? The new fuse is holding in my driveway but it had to have blown for a reason so I don't trust it. My car is a 2011 335i n55 e90. Thank you in advance

[gbalthrop]

F37 is not important, it's only the primary power to the DME.
Attached is the ISTA SSP wiring diagram for F37 circuit on 2011 335i N55. Depending upon amount or rain, road
water, etc. It MAY have just been a hiccup/defective fuse. Was it 30-Amp capacity, & did you use 30A replacement?

If F37 blows again, I would electrically test for resistance in reference to ground (test for short to ground) of that
Red/White wire to X6011/3, and the Red/Green wire from X6011/3 (Connector as shown in E-box in ISTA
ScreenPrint) to X60005/12 at the DME. Those tests are done with connectors DIS-connected, simply a wire test.
George

[PNWn55]

Originally Posted by gbalthrop

F37 is not important, it's only the primary power to the DME.
Attached is the ISTA SSP wiring diagram for F37 circuit on 2011 335i N55. Depending upon amount or rain, road
water, etc. It MAY have just been a hiccup/defective fuse. Was it 30-Amp capacity, & did you use 30A replacement?

If F37 blows again, I would electrically test for resistance in reference to ground (test for short to ground) of that
Red/White wire to X6011/3, and the Red/Green wire from X6011/3 (Connector as shown in E-box in ISTA
ScreenPrint) to X60005/12 at the DME. Those tests are done with connectors DIS-connected, simply a wire test.
George

Originally Posted by gbalthrop

F37 is not important, it's only the primary power to the DME.
Attached is the ISTA SSP wiring diagram for F37 circuit on 2011 335i N55. Depending upon amount or rain, road
water, etc. It MAY have just been a hiccup/defective fuse. Was it 30-Amp capacity, & did you use 30A replacement?

If F37 blows again, I would electrically test for resistance in reference to ground (test for short to ground) of that
Red/White wire to X6011/3, and the Red/Green wire from X6011/3 (Connector as shown in E-box in ISTA
ScreenPrint) to X60005/12 at the DME. Those tests are done with connectors DIS-connected, simply a wire test.
George

Wow thanks George this is super helpful! After digging I couldn't find info on fuse 37 for my car. The fuse that I pulled out was actually a 15a so that's weird. Maybe it blew because it's undersized but I've had the car for a year and a half and never had an issue. I may throw a 30 in after troubleshooting. Thanks again!

[PNWn55]

Originally Posted by gbalthrop

F37 is not important, it's only the primary power to the DME.
Attached is the ISTA SSP wiring diagram for F37 circuit on 2011 335i N55. Depending upon amount or rain, road
water, etc. It MAY have just been a hiccup/defective fuse. Was it 30-Amp capacity, & did you use 30A replacement?

If F37 blows again, I would electrically test for resistance in reference to ground (test for short to ground) of that
Red/White wire to X6011/3, and the Red/Green wire from X6011/3 (Connector as shown in E-box in ISTA
ScreenPrint) to X60005/12 at the DME. Those tests are done with connectors DIS-connected, simply a wire test.
George

Update: I replaced the fuse and it held so I hadn't gotten around to troubleshooting any further. It lasted until last week and is now blowing fuses every time I replace it. I have done some troubleshooting and this is what I found:
I tested the red/white wire from fuse 37 and through that under hood plug it changes to red/green then heads to the dme. Neither show a short (the red/white to ground and then the red/green to ground). I traced back to the dme and found which pin that wire connects to at the dme connector and again no short to ground.
I unplugged both the under hood red/white to red green connector- and the dme plug and put a new fuse in. I plug in the red/white-red/green connector and fuse is still good. But the second I plug into the actual dme the fuse blows. Do I have a short in the dme? I tried to test the actual terminal on the dme but it doesn't ring out (continuity to ground) TIA

[hushlight6]

Did you solve the problem? I keep blowing my FUSE 37 and Im not sure if my DME is fired

[PNWn55]

Originally Posted by hushlight6

Did you solve the problem? I keep blowing my FUSE 37 and Im not sure if my DME is fired

I sent my dme off for testing and there was nothing wrong with it. It ended up being the pcv heater going out. After replacing that and securing it off to the side I had no issues anymore. I had installed a bms catch can a few months prior so it must have just went bad from rattling around beings it was just tucked off to the side.

[328x drive]

Originally Posted by gbalthrop

F37 is not important, it's only the primary power to the DME.
Attached is the ISTA SSP wiring diagram for F37 circuit on 2011 335i N55. Depending upon amount or rain, road
water, etc. It MAY have just been a hiccup/defective fuse. Was it 30-Amp capacity, & did you use 30A replacement?

If F37 blows again, I would electrically test for resistance in reference to ground (test for short to ground) of that
Red/White wire to X6011/3, and the Red/Green wire from X6011/3 (Connector as shown in E-box in ISTA
ScreenPrint) to X60005/12 at the DME. Those tests are done with connectors DIS-connected, simply a wire test.
George

[328x drive]

Maybe some one can help. My bmw E90 328xi N51 crank no start. Checked voltage fuse 37 7.9V 38 and 39 the same!?

[gbalthrop]

Originally Posted by 328x drive

Maybe some one can help. My bmw E90 328xi N51 crank no start. Checked voltage fuse 37 7.9V 38 and 39 the same!?

If that is 2009 model, all 3 of those fuses are powered when the DME Main Relay, K6300, is activated, Ignition ON.
Easiest thing to check: X11010 connector on Upper-Right of JB Fuse Panel, beneath Glovebox. Pin #1 is ground from
DME to Activate K6300 Electromagnet. Make sure that connector is firmly attached. If so, & still "Crank, NO Start", or
NOT battery voltage at F37, then remove connector X11010 & clean pins/sockets with Electronic Contact Cleaner.

I assume your interior lights, IHKA Control Panel & Blower work correctly with ignition ON? If so, your power to JB Fuse Panel
is OK, and the issue is in the Activation wiring of the K6300 Relay, or the relay itself. The K6300 relay is soldered to the
JB Printed Circuit Board (PCB), but seldom fails. Is there any "Relay Chatter" or repeated "Clicking" when Ignition is ON?

ISTA ScreenPrints are attached showing the described fuse circuits & Connector Location & View. Try the steps
suggested above & let us know what you find. If NO change in voltage at fuses 37-39, we can suggest next steps.
George