Ah man... I just had a look at my images and i see the SMD labeled F1. Never even came close to the realization that it could be a fuse. I had thought all surface mount fuses were cylindrical shaped.

I just went to the garage to find both of my old boards and give them a test. Both of my fuses lack conductance too. A quick google finds that exact fuse as being made by KOA with model CCF1N8TTE. Roughly $1 per fuse.

Please let me know how shorting out the fuse works for you. Just remember that your fans wont be guaranteed to spin unless the battery temp is 75F or higher. If you get them to spin with the shorted fuse then I'll likely undo my work and just replace the fuse to restore factory operation.

I think we all owe your friend a beer for noticing that fuse!


EDIT: was too excited about the fuse and forgot about your question. The blue wire is linked to both the key as well as the battery conditions. It will occasionally blip on at around 50F or 60F, but usually turns back off after a few seconds (as if it were a self test). It is guaranteed to be on when the battery temp is over 75F. See comment #18 on the other thread for more details.

The fuse being 8amp makes a ton of sense given the 6.7 max draw i saw. I could definitely see a momentary spike of 8 amps happening and blowing the fuse. I'm still debating, but i'll either replace mine with either 9a or 10a to avoid unnecessary triggers .. or jump the smd fuse and install an 8 amp auto reset breaker upstream (around $8).

 

Thank you very much for detailing that for me! Definitely not warm enough to trigger fan spin, and I'm not fast enough to turn the key, run back and check the DMM. I did mark the fans and they never moved.
Great Idea, I've got in line fuse holders coming to wire into the leads, but there are breakers available to insert into them.

There has to be a reason to blow a fuse. Under the aluminum heat sink is more than likely the driver ic. That's my guess at the failure culprit
https://www.digikey.com/en/articles/...less-dc-motors
The white heat sink compound feels like RTV. It may have degraded and stopped conducting heat causing failure,,,,,,,Best guess

I'm going to try to de-solder the motor winding on mine and get the chip p/n to replace them.

 

The chip under the heatsink is a 6AM15. (my board was still sitting beside me)
https://4donline.ihs.com/images/VipM...A73243A3159BB0

My trick was just to check after i got home from my daily commute to work.

 

Thank you again! I owe you a cold adult beverage

I'm sure your looking, but I can't find any replacements except for ebay
I'll have to bug my neighbor again to help cross reference. I got it narrowed down a little
https://www.digikey.com/short/pjh81t

 

I hadn't started looking for any replacements yet. Might be worthwhile to do a test before attempting to source more components. I'd suggest bypassing the fuse by soldering a wire to each end of the fuse and bringing them out of the case. Can then wire in a regular 7.5a or 10a auto fuse. If the fan runs normally then we can probably assume it was just a high startup current that blew it. If it insta-blows as soon as the fans try to turn on then it's likely another bad component.

...when parked and below 90F the current draw in ICE mode is around 2 amps and around 1.3 amps in EV mode. Doubt the startup surge would surpass the 7.5a auto fuse (might even be able to use a 5a).


Edit: around $8 shipped from china for 2 of them: https://www.aliexpress.com/item/6AM1...006048303.html


Edit2: From your filtered result list, it looks like SLA5064 is the match. However, they're $7.4 each, plus shipping.
https://www.digikey.com/product-deta...064-ND/3661857

 

[QUOTE=btarb24;267764]Might be worthwhile to do a test before attempting to source more components. I'd suggest bypassing the fuse by soldering a wire to each end of the fuse and bringing them out of the case. Can then wire in a regular 7.5a or 10a auto fuse. If the fan runs normally then we can probably assume it was just a high startup current that blew it. If it insta-blows as soon as the fans try to turn on then it's likely another bad component.
[QUOTE]

Did some bench testing last night, bypassed the blown fuse and put 12 volts to it. My Driver IC is definitely blown.
I got it off, nice **** stain on the case where one of the MOSFETs blew it's guts out.

Thanks for confirming my neighbor's and my cross reference. I'll look a bit and see if I can get an original that doesn't ship on a slow boat.

MY video of the teardown

Edit
Can't get digikey cart to work. Found the SLA5064 for $1.70 each with 2 week shipment. I got extras Will report back later

 

Thanks for the video.

One other concern might be that you were lacking the PWM yellow lead. That one seems to control the speed of the fan spin ... no signal might be an invalid situation for the board that causes a no spin, but still a draw on the mosfet (who really knows). Mine doesn't show any discoloration or signs of heat on either side of the chip or board, but my fuse is certainly blown.

I've been down with the flu for the last 2 weeks so i haven't been commuting to work. Whenever i finally kick the cough i'll start heading into the office again and the commutes generally get me up to fan temp. The plan is to wire one of the boards into the car with a bypassed fuse to see if she chooches. If so then i'll know my only problem was the fuse. If not, then we'll give the mosfet a whirl. You will probably beat me to the punch, but i'll still do the test just in case it turns out to only be the fuse.

Between the two of us it seems like we might get a pretty solid picture on the core problem along with some cheap instructions for others to use.

 

First time I powered it up was just the red 12v and black ground, and it already started to get hot. I tried applying 12v to the blue the second time.
The mosfet was certainly bad when I started. I bet it could be changed without pulling the winding wires. It's a gamble if the rest of the board is still good.

Thanks for the encouragement, hope we can figure it out. I've got an o scope, so once it warms up a bit I hope to get more information on that signal wire.
But I'd be happy to just get them to spin

Get well soon!

 

Got my replacement chips in the mail today, direct from far off lands

Replaced them and got one fan almost assembled. Should be able to test it this week.

Wish me luck

 

No joy
I replaced the mosfet driver chip on my bad fan and plugged it in. Before it popped the fuse it managed to let all the smoke out.
Something else must have gone bad on the board.
If you want to try one btarb24, I have several. Email me at thommyknocker.th@gmail.com and ill send you one,


I do have good news! FORscan can perform a BCM test and force fan spin.



I can confirm your wire designations
Red= +12v
Black = ground
Blue = +12 volts when fan spin is called for, its not DC but a very fast PWM ac signal.
Both Brown and Yellow wires appear to have similar PWM shown below
I tried to get a good pic of the PWM signal



I thinkmy next step will be to follow you and try a brushless driver

and here is a mosfet I found that isnt too big, Ill try to use the blue wire to trigger this

Thom