Quote from Kamil Singh on May 13, 2024, 10:29 am

I have seen this done many ways already. All methods will need a fan switch installed into the thermostat housing which turns on at a temperature thats over the temperature that your thermostat opens.The first one I saw was one or two of those universal electric fans that come with straps that mount thru the radiator core.  There you can just use a normal 4pin relay because they are low power fans.  But this method is not very efficient because the fans don't really move air thru the entire radiator but just the areas that they are mounted.     The next was a fan with shroud assembly from an older golf made to fit over the radiator .also low power so wired up the same but the nicest one was a fan assembly from  a late model w202 . Those are high power and  run with a fan module and get a pwm signal from the ecu to regulate fan speed.  So they can't be connected direct to a switch or the car will sound like jet when it comes on.  So to make it work you need the module(see picture) and a universal pwm fan speed controller and you can set the fan to the necessary speed for your application.   Maybe there are some better ideas out there.   Let me know how you decide to get it done.