Quote:
Originally Posted by joedoh
sorry, i missed that. reading back, fan 1 is for low speed? and fan 2 is for high speed? you can only use that on fans that have a separate low speed and high speed wire (three wires total). if your fan has two wires (power and ground), you can use either fan 1 or fan 2 output from pcm and the fan will run full speed. if you have a fan with 3 wires and two speeds, you will need two relays, which it sounds like you have in the harness? the 12v supply should be in parallel
older BMWs had big giant fan resistors on a 2 wire fan, so that a fan 1 signal went through the resistor, and fan 2 signal bypassed it, making a 2 wire fan a 2 speed fan, but the resistors predictably went bad all the time from the super high current being resisted, 12v at 30 watts us 3600 watts, cutting down the speed took about a 1/4 of that, so the resistor was in the area of 900watts! the resistors on the shelf at radio shack are 1/4 and 1/2 watt, so a fan resistor was huge and packed in sand to dissipate the heat of resistance (thats where the energy goes, 900w turned into heat and 2700 watts goes on to the fan)
|
Hey Joe.
Yeah I have only a single speed main FAN for radiator/cooling and a single speed condensor fan. Didnt really need to but this DIY fuse block.
The BP fuse block relay DIY has two relays and just says FAN#1 and FAN#2 - doesnt have details about how those relays are configured. So my plan (originally) was to try and do the following
* AC on a dedicated circuit outside of PCM. Single standalone relay
* FAN#1 would be PCM controlled and tied to my single speed main radiator fan.
If I tried to use two relays for the AC/condensor fan (to split like you mentioned ) ... I'd like to use FAN#2 relay .... as otherwise its just sitting there unused. But hard to know how they set it up without tearing it all apart which I will probably do.
All they say is
"Two Fan Relays, an A/C Compressor Relay, and an Ignition Relay"
https://www.bp-automotive.com/produc...i-24x-engines/
<update>
I jumped on the webiste chat room and the guy said ...
"They are parallel. They are not in series."
So I guess that means I could use it ........ except ground would only activate when fan temp reached whatever point I set in PCM ?