As I was researching some fan control circuitry I was wondering if anyone on here has ever opened up the fan control module? Seems if the RCM is prone to bad solder connections the FCM might be as well.

 

Beaner and I opened his up. Appears to be a circuit board with relays however, I know nothing about electronics.

 

Still have it? I would be curious as to the type of connections from the wiring harness connector to the PC board. It's those 90 degree big metal pieces going from the harness connector to the PC board in the RCM that vibrate loose and I suspect it might be the same for this module.

 

Yes I still have a few of them around here
No way for anything in there to vibrate loose. trying to get it apart is not the easiest task
Mine was intermittently working. (tested multiple times in another crossfire which had no issues to verify)
No signs of faulty solder connections, no burnt smells, no discoloration or visual signs of any malfunction to board and everything on it...

 

Thanks for posting those. It looks simpler than I thought. The row of pins an inch or so up in the last pic are the suspect pins but after seeing these I wonder if the row of FET's could have a bad one or two. Maybe even a bad cap. You have a multimeter?

Thinking out loud here I wonder if the row of FET's is turned on sequentially to increase speed or they are all in parallel switched on at the same time to regulate the speed of the fan.

By this one being intermittent do you mean never work then working OK or would it only work at low speed but not high speed?

 

Sometime works, some times not... there was no "works a little", just a does or does not.
multimeter yes, Will I test it more than what I did no. I know some part of it is faulty, the cost to swap the part is not worth the time to mess around and get it working properly again. Car will run and drive without it but don't get caught in traffic haha

 

Awesome questions, yeah baybee! Sounds like a seasoned troubleshooter in the loop!

 

Well seasoned....... LOL


Or maybe just old........

 

Maybe BOTH? LMAO...

 

GraphiteGhost didn't say it, but I will.
You would sure make his day if you would send it to him to play with ( since you said you were done with it ).
He's been asking for one for close to 3 years now.

OOOPS !!! Forget it, George was looking for a CLIMATE control module, not a FAN control module. My bad.

 

That board was built about the same time I had a TV problems. Found that China had made bad capacitors.

 

Hey George, thanks for helping out. On a side note, your going to experience a lot more Oooops's as you go. Its happening more and more to me (I think it is age related). He he he he he

 

Klay, it sure could be bad solder, but how many switching power supplies have you seen fail? For me, it's more common than the old linear regulated ones. The FCM is, somewhat, a switching supply but one that provides a regulated, varied output instead of a regulated, steady output.

It has two jobs:
The FCM takes a PWM signal from the PTCM and turns around and responds with a "I"m here" pulse to the PTCM.

It also takes that PWM signal and PWMs the 12 volts to the fan motor.

 

Or I would like to test the FET's on the board of a bad FCM. Maybe even find the part no. and replace them to see if the FCM can be fixed.

 

From what I have found is that it feeds a pwm 12 volt signal and the motor is run most of the time at about 4 volts (average volts) , if you feed direct 12 v to the fan it will scare you with the speed and noise. I have been thinking of adding one to allow for higher speed cooling for those that are in line at the drags. Speeding up the fan is a function of the voltage applied. Wdy