Hi all, this sounds easy enough right?
I will keep it as short as possible, please ask questions that you feel need answering.
My vehicle used to have a two speed electric cooling fan fitted, the speeds indicated by two 12v LED's in a custom built module in my vehicles dashboard. These were fed via the same relays that switched the fan speeds, the relays controlled by a combination of engine temperature fan switches and AC presure switches. This has worked fine for years but the fan now getting old and OE fan replacements no longer available, copies are poor quality, so the decision was made to move to a more modern fan.
My choice was dictated by a website stumbled on during my search for the replacement fan a Mercedes unit, but it is controlled via PWM. There is a supplier of controllers designed specifically for the Mercedes fan and he confirms that it should work with my system however, his dashboard mounted LED changes colours dependant on the fan speed related to engine temperature, and uses an LED that has a much lower voltage rating than my 12v unit. My custom dashboard display cannot be modified to accept his multicoloured LED so, I am looking for a way to use the PWM signal that tells the fan to start spinning to trigger a 12v supply to my present LED.
I have asked the controller supplier about this but have not had a reply yet so, in the meantime I am researching to see if it is something I can purchase 'off the shelf' or even build myself? I may be wasting my time (and yours) as the supplier of the controller may already have it sorted?
Given my limited electronics knowledge I gather the PWM signal changes to control the fan speed so guess this adds some complexity?
A mechanic by trade, I have worked with relays in the fuel system that receive a signal from the ecu to keep a 12v relay active and supply 12v to the fuel pump, that more or less covers my knowledge in this area, but hope you get my way of thinking here?
Any thoughts on this guys and girls?
Regards
Dave
I will keep it as short as possible, please ask questions that you feel need answering.
My vehicle used to have a two speed electric cooling fan fitted, the speeds indicated by two 12v LED's in a custom built module in my vehicles dashboard. These were fed via the same relays that switched the fan speeds, the relays controlled by a combination of engine temperature fan switches and AC presure switches. This has worked fine for years but the fan now getting old and OE fan replacements no longer available, copies are poor quality, so the decision was made to move to a more modern fan.
My choice was dictated by a website stumbled on during my search for the replacement fan a Mercedes unit, but it is controlled via PWM. There is a supplier of controllers designed specifically for the Mercedes fan and he confirms that it should work with my system however, his dashboard mounted LED changes colours dependant on the fan speed related to engine temperature, and uses an LED that has a much lower voltage rating than my 12v unit. My custom dashboard display cannot be modified to accept his multicoloured LED so, I am looking for a way to use the PWM signal that tells the fan to start spinning to trigger a 12v supply to my present LED.
I have asked the controller supplier about this but have not had a reply yet so, in the meantime I am researching to see if it is something I can purchase 'off the shelf' or even build myself? I may be wasting my time (and yours) as the supplier of the controller may already have it sorted?
Given my limited electronics knowledge I gather the PWM signal changes to control the fan speed so guess this adds some complexity?
A mechanic by trade, I have worked with relays in the fuel system that receive a signal from the ecu to keep a 12v relay active and supply 12v to the fuel pump, that more or less covers my knowledge in this area, but hope you get my way of thinking here?
Any thoughts on this guys and girls?
Regards
Dave