[DadBodWorkshop]

I have read dozens of these similar threads but can not find any solution. Our car overheated and left us stranded. We checked for codes prior to leaving for our trip and had no codes relating to water pump. Then we overheated and got 2E84 (Water Pump Missing). We had to pay a small fortune to get it towed back home and I started digging into these issues. Here's what I've tried:

Checked junction box on top of battery and verified continuity through all leads and all tested normal. Checked for corrosion at same time and found nothing abnormal.

Checked fuses under glovebox and couldn't find anything blown. I wanted to full the entire fuse box out but couldn't because I don't have my proper tools with me.

Checked fuse box inside engine bay and my box only has one 40A fuse in it. I looked all around, pulled out relays, etc and could only find the one fuse. The 40A fuse is fine.

I checked the 4 pins coming off the water pump harness. Pin 4 (Ground) has good connection to the frame of vehicle so the ground is good. Pin 1 (12v+) has 0 volts. Pins 2 and 3 also show 0 volts. My understanding is that pin 1 should always have 12V supplied. I also tested it with ignition on, engine off with same results.

I traced the Pin 1 wire up through the engine bay and into the engine fuse box. Continuity was good between Pin 1 at the water pump harness and at the engine fuse box. As I chased the wire through the engine bay, I noticed it has no fuse or relay. It passes straight through to the fuse box inside the glovebox. The wire comes into the engine box as a thicker red wire, goes into a wire connection clip and then goes into the glovebox fuse box as a Red/Green wire.

At this point, I'm confused on where to go. My understanding is that if the B+ cable is bad it will cause a lot of issues with the car, not just the water pump. All the writeups I've found people mention to check F07 or F09 inside engine box but I literally have a single fuse in there and it's good. I'm confused where to go next, I'll continue checking fuses when I get time but I could really use some help figuring out the rest of this. For obvious reasons, the car will not perform a manual water pump flush even after performing the procedure many times before this incident.

[hugorruss]

Heya,

I can confirm that with ignition on you should be getting voltage to those wires. I just tested this yesterday on 07 335i.

I would have a look at this video:

It could be a blown internal fuse in the "wire delivery harness" that sits on the battery. The above video shows you how to test it.

Other thing I would check is the fuses that are in the little black box in the engine fuse box. It is sitting right next to the DME, right in front of it. There is a fuse in there that can also disrupt power to your water pump.

I'd recommend getting INPA up and running, it's really not that hard, I am a newbie with it and was really easy. Google translate app on your phone has a "camera" function that will translate everything for you in realtime, just aim it at the screen

Good luck.

[F31B48]

Check fuse 37 and 33. They are the water pump fuses. 37 (30a) is for pin 2, 33 (40a) is for pin 1.

If you're working on the car yourself you should really get ISTA factory BMW diagnosis software which also has wiring diagrams and repair instructions for replacing parts. It's free to download on this forum.