I am working on wiring the ventilated portion (a fan) of an automotive seat. The fan has 3 wires coming from it, then it also has an additional ground wire. The ground wire does not go to the connector plug, but rather is attached to the metal base of the fan.
The connector for the fan has 3 wires. Per the wiring diagram:
Black - Ground
Red - Power
White - PWM Control
Blue - additional ground
In the vehicle where the seats were originally installed there is obviously a fancy computer system that controls the speed of the fan. I would be happy to simply run the fan at full speed.
What I have discovered, through some trial and error (and some dumb luck). If I connect the Black to ground, Blue to ground, and Red to 12v the fan does nothing. However, if I also apply ground to the white wire in an off/on/off/on sequence after a few times the fan kicks on. It seems I need to continue with that sequence or the fan shuts off.
Is there an easy way to get it run at full speed? If not is there a PWM that i can add to the wiring that will create an ON/OFF to ground for the white wire?
The fan is made by Gentherm, but I can't find any detailed info about it.
@gilshultz I posted what each wire is for. There is a positive and negative. The third wire is a PWM control. I need to be able to do something with that PWM wire to make the fan operate at max speed.
Use the PWM output of one of the Arduino's. Just be sure to isolate it using a MOSFET or ss relay. I have no idea how much current or what PWM frequency it will require. The reason I asked is some motors are connected to a motor controller that communicates via CAN to possibly the body computer, varies by make and model. Sometimes schematics for those can be obtained from the dealer or modules that you can communicate with. Is this going in a vehicle? If so have you had any experience in automotive electronics at the module level?
Yes it is going into a vehicle. It seems the PWM on this fan needs a grounding signal instead of a + signal. Take a look at video in my first post.
In it's original configuration (2022 Grand Cherokee) it definitely communicated to the body computer, so I suspect it was getting some fancy signals. I would be happy to just have it run on high speed.
I never said +, Using a MOSFET with an open drain configuration or a ss relay would do the job. Post your preliminary annotated schematic, show all connections and interface to the 12V electrical system and what your final driver for the PWM to the fan will be. Hint, I do not do with word problems or frizzy pictures. Good luck generating the "fancy signals". You may be able to do this with a LM555 and a few components. You can also buy PWM modules on line for a few $$$.
@gilshultz , my apologies about the +. Thank you for the information. I don't think I'm after the fancy signals, assuming i can make it run on high speed with a simple signal. I think the fancy signals would be for a high medium and low speeds.
Unfortunately, I don't really understand most of what you are talking about. I'm going to try and do some research to understand the parts you are referring to.
Any recommendations on where i would purchase the parts your reference.
I would recommend parts but not the source and many times not the manufacturer. If you have some friends that like electronics give them a try, this is stuff many will understand.
Black - ground
Red - 12v
White (PWM) - 12v and the fan does not turn on at all
In the video:
Black - ground
Red - 12v
White - I am moving it back and forth on ground (the metal plate I am moving it on is grounded). I believe as i am moving it it is like quickly breaking connection and creating an OFF/ON/OFF/ON situation which then activates the fan.
The one Amazon says not for brushless motors. The one Ali say brushless motors. I am going to assume the motor I am working with is brushless.
If I understand these BLDC drivers correctly they modulate the + voltage that goes to a motor, basically turning it on and off at a particular frequency. I "believe" I need something like that, but to turn on and off a ground connection. (I am still not 100% sure that is what will correctly drive this fan). Can this BLDC be wired such that it will turn the ground on and off instead of +?
When I checked the number for the motor you showed earlier ALL references were for BLDC.
Currently you have it "jerry rigged" so your present method might actually be incorrect..
You can "kick start" BLDC motors and I think that's what you are doing at the moment.
