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General => General Technical Chat => Topic started by: administr4tor on May 01, 2026, 04:02:41 pm

Title: help finding replacement for this BLDC fan controller
Post by: administr4tor on May 01, 2026, 04:02:41 pm
(https://i.postimg.cc/QC69cxXg/f1.jpg)
(https://i.postimg.cc/5yPY8NxB/f2.jpg)
(https://i.postimg.cc/6qH2C59d/f3.jpg)
(https://i.postimg.cc/sxnQ5DVW/f4.webp)
[/img]



(https://i.postimg.cc/DZbdnNKq/image.png)
its for a Radiator Fan for automobile car
OEM part is out of stock

any way I can find a replacement part for it somewhere?

please help

THanks
Title: Re: help finding replacement for this BLDC fan controller
Post by: Randy222 on May 01, 2026, 05:39:35 pm
Inside that box is likely just a FET with a pull-down resistor. It may also have a zener or diode to squash flyback.

The FET gate may also have a small resistor on it, but the device looks automotive, and many times the ECU control line has the resistor in the ECU.

The ENABLE line can just be an SSR, so it provides power to the ckt, but the FET swicthes the motor on/off to the beat of BLUE PWM.

The wire-gram on unit shows 6 connections, but the 3 connectors have 8 ??

Making the device should be very easy.
Title: Re: help finding replacement for this BLDC fan controller
Post by: Uunoctium on May 01, 2026, 05:45:01 pm
Comex is still alive and produces three different types of fan controllers. You may write them an email and ask, if one of the types is suitable as an replacement for your damaged one. (probably only with some modifications eg replacing the NTC with an fixed resistor).

https://www.comex-europe.com/cms/en871-electronic-speed-control.asp (https://www.comex-europe.com/cms/en871-electronic-speed-control.asp)
Title: Re: help finding replacement for this BLDC fan controller
Post by: thm_w on May 01, 2026, 10:06:33 pm
ebay: https://www.ebay.ca/itm/314431717115 (https://www.ebay.ca/itm/314431717115)
auto wrecker

Is it the same as this one? https://fortnine.ca/en/triumph-fan-pwm-controller-t2507700 (https://fortnine.ca/en/triumph-fan-pwm-controller-t2507700)
Title: Re: help finding replacement for this BLDC fan controller
Post by: Randy222 on May 03, 2026, 12:56:59 am
That one from CA site, $327(CAN) !!
Yikes, can build probably a dozen of them from discrete parts for that price.

Buying a cots is always easier, but I do evaluate DIY.
Title: Re: help finding replacement for this BLDC fan controller
Post by: amyk on May 03, 2026, 02:05:57 am
My guess is the inside has not much more than a relay and two FETs, and maybe a few passives.

"Don't turn it on, take it apart!" :D
Title: Re: help finding replacement for this BLDC fan controller
Post by: administr4tor on May 03, 2026, 08:43:14 pm
yeah, thats one of the reason I am trying to find alternate, why pay $350 when you get it cheaper elsewhere?


I found this, do you think it will work? the Audi one is rated for 60A, while Triumph one is rated 20A (?) atleast thats the fuse I see in Triumph diagram.


https://www.amazon.com/-/fr/No-8E0959501AG-8E0959501AB-8E0959501K-ventilateur-refroidissement/dp/B0CHS8X9QW (https://www.amazon.com/-/fr/No-8E0959501AG-8E0959501AB-8E0959501K-ventilateur-refroidissement/dp/B0CHS8X9QW)
(https://i.postimg.cc/rptxCT9S/image.png)


below is PIN out and OEM Audi Electrical diagram for the Audi cooling fan PWM module


(https://i.postimg.cc/6qzMJKgC/image.png)



if you think it will work, what pins replace what pins , i need conversion of pins between amazon and triumph module, based on information above.

Thanks for helping me out


My guess is the inside has not much more than a relay and two FETs, and maybe a few passives.

"Don't turn it on, take it apart!" :D
That one from CA site, $327(CAN) !!
Yikes, can build probably a dozen of them from discrete parts for that price.

Buying a cots is always easier, but I do evaluate DIY.
ebay: https://www.ebay.ca/itm/314431717115 (https://www.ebay.ca/itm/314431717115)
auto wrecker

Is it the same as this one? https://fortnine.ca/en/triumph-fan-pwm-controller-t2507700 (https://fortnine.ca/en/triumph-fan-pwm-controller-t2507700)
Comex is still alive and produces three different types of fan controllers. You may write them an email and ask, if one of the types is suitable as an replacement for your damaged one. (probably only with some modifications eg replacing the NTC with an fixed resistor).

https://www.comex-europe.com/cms/en871-electronic-speed-control.asp (https://www.comex-europe.com/cms/en871-electronic-speed-control.asp)
Title: Re: help finding replacement for this BLDC fan controller
Post by: administr4tor on May 11, 2026, 08:06:30 pm
:bump:
Title: Re: help finding replacement for this BLDC fan controller
Post by: Randy222 on May 12, 2026, 05:55:27 am


I found this, do you think it will work? the Audi one is rated for 60A, while Triumph one is rated 20A (?) atleast thats the fuse I see in Triumph diagram.


https://www.amazon.com/-/fr/No-8E0959501AG-8E0959501AB-8E0959501K-ventilateur-refroidissement/dp/B0CHS8X9QW (https://www.amazon.com/-/fr/No-8E0959501AG-8E0959501AB-8E0959501K-ventilateur-refroidissement/dp/B0CHS8X9QW)
Is the plug a direct fit? I can say with 100% certainty, it may or may not work.

The original side label only shows one (M) motor, so probably the two "white" connectors for fans are wired in parallel. It is very likely to be a current sink controller. Two nFET's in series, yellow gates one, the blue PWM turns on/off the 2nd FET. Yellow (ignition) so that the fans cant stay running after the key has gone to off.

Probably just easier to build a replacement.
IRF low Rds very high amps, decent 40v, use diode to quench flyback
IRFB7434PBF

1k pull-down on gates.

Plenty of helpers around on this site to drum up schematic as needed.

Title: Re: help finding replacement for this BLDC fan controller
Post by: Smokey on May 12, 2026, 07:40:42 am
BLDC = brushless DC electric motor
https://en.wikipedia.org/wiki/Brushless_DC_electric_motor

Title: Re: help finding replacement for this BLDC fan controller
Post by: administr4tor on May 13, 2026, 11:16:29 pm
how do I make my own?
Title: Re: help finding replacement for this BLDC fan controller
Post by: Randy222 on May 13, 2026, 11:21:43 pm
how do I make my own?
Start a thread in the Projects forum.
"Need Schematic For DIY Controller"

It's very simple to make.
Title: Re: help finding replacement for this BLDC fan controller
Post by: aeg on May 14, 2026, 03:05:18 am
I think the mechanical and thermal aspects are the hard part...
Title: Re: help finding replacement for this BLDC fan controller
Post by: Randy222 on May 14, 2026, 03:28:23 am
I think the mechanical and thermal aspects are the hard part...
What mechanical aspects?

Some discrete components potted. Should be no issue for automotive use.

Something like this she-matic. ;)

(https://myimgs.org/storage/images/20895/she-matic.png)