albersondh
07-03-2010, 01:09 AM
This is how I did mine. Its not as good as a full on IC logic controller but it gets the job done. Why its good.
- When the hi side adjustable fan switch kicks on, it kills power to the low side fan switch. Only one set of the fans windings can be active at a time. This may extend the life of the fan, and will certainly lower the continuous current draw.
- Its full adjustable. You decide when low kicks in and when high kicks in, and you set the low to high overlap.
- Adjusted correctly it will overlap from low to high. This means the fan is already moving and the inrush current requirement to get high moving is much lower than if the fan were not moving. I run a 40A fuse on high and it has never blown.
- My low is on at 180 off at about 187. The only time high comes on is in traffic on a 90*+ day in traffic with the AC on blast (5.2L OE radiator).
- Its cheap. Shouldn’t run over $100 in parts.
BOM:
qty 2 sealed standard automotive relays 30A rating. $8.75 x2 http://www.wiringproducts.com/contents/en-us/d36.html (http://www.wiringproducts.com/contents/en-us/d36.html)
qty 1 BWD S672 80A continuous duty Solenoid $29 http://www.oreillyauto.com/site/c/detail/BOR0/S672.oap?pt=N0791&ppt=C0218 (http://www.oreillyauto.com/site/c/detail/BOR0/S672.oap?pt=N0791&ppt=C0218)
qty 2 Hayden pn# 3653 (or higher quality equivalent). $23 x2 http://www.summitracing.com/parts/HDA-3653/ (http://www.summitracing.com/parts/HDA-3653/)
Miscellaneous:
Appropriate AWG wire and qty 2 30A fuses, qty 1 40A fuse.
Notes:
I get power from the fuse/relay box main power lug and ground to appropriate chassis grounding points. I tapped the main OE harness coming from the fire wall on the PS for my ign 12V (make sure its a circuit that can handle 10 or more amps for powering the relay coils). The cheapo thermo-switches close circuit when they get wet so mount them high. I seal them up with liquid electrical tape and mount them high, never had an issue with them closing when wet. Bathroom silicone caulk would work as well, just seal the shit out of them and no worries. You could easily integrate a "fan on" light and a fan kill switch into this mess if you were so inclined, mounted in the cab. Kill switch would be for fording, ect. The two relays fit nicely in in the existing fuse/relay box and the lid closes just fine.
http://i151.photobucket.com/albums/s150/albersondh/fan/Fancurcuit1.jpg
http://i151.photobucket.com/albums/s150/albersondh/fan/DSC03449.jpg
http://i151.photobucket.com/albums/s150/albersondh/fan/DSC03451.jpg
http://i151.photobucket.com/albums/s150/albersondh/fan/DSC03452.jpg
http://i151.photobucket.com/albums/s150/albersondh/fan/Fanswitch.jpg
http://i151.photobucket.com/albums/s150/albersondh/fan/Fanswitch2.jpg
http://i151.photobucket.com/albums/s150/albersondh/fan/Fanswitch3.jpg
- When the hi side adjustable fan switch kicks on, it kills power to the low side fan switch. Only one set of the fans windings can be active at a time. This may extend the life of the fan, and will certainly lower the continuous current draw.
- Its full adjustable. You decide when low kicks in and when high kicks in, and you set the low to high overlap.
- Adjusted correctly it will overlap from low to high. This means the fan is already moving and the inrush current requirement to get high moving is much lower than if the fan were not moving. I run a 40A fuse on high and it has never blown.
- My low is on at 180 off at about 187. The only time high comes on is in traffic on a 90*+ day in traffic with the AC on blast (5.2L OE radiator).
- Its cheap. Shouldn’t run over $100 in parts.
BOM:
qty 2 sealed standard automotive relays 30A rating. $8.75 x2 http://www.wiringproducts.com/contents/en-us/d36.html (http://www.wiringproducts.com/contents/en-us/d36.html)
qty 1 BWD S672 80A continuous duty Solenoid $29 http://www.oreillyauto.com/site/c/detail/BOR0/S672.oap?pt=N0791&ppt=C0218 (http://www.oreillyauto.com/site/c/detail/BOR0/S672.oap?pt=N0791&ppt=C0218)
qty 2 Hayden pn# 3653 (or higher quality equivalent). $23 x2 http://www.summitracing.com/parts/HDA-3653/ (http://www.summitracing.com/parts/HDA-3653/)
Miscellaneous:
Appropriate AWG wire and qty 2 30A fuses, qty 1 40A fuse.
Notes:
I get power from the fuse/relay box main power lug and ground to appropriate chassis grounding points. I tapped the main OE harness coming from the fire wall on the PS for my ign 12V (make sure its a circuit that can handle 10 or more amps for powering the relay coils). The cheapo thermo-switches close circuit when they get wet so mount them high. I seal them up with liquid electrical tape and mount them high, never had an issue with them closing when wet. Bathroom silicone caulk would work as well, just seal the shit out of them and no worries. You could easily integrate a "fan on" light and a fan kill switch into this mess if you were so inclined, mounted in the cab. Kill switch would be for fording, ect. The two relays fit nicely in in the existing fuse/relay box and the lid closes just fine.
http://i151.photobucket.com/albums/s150/albersondh/fan/Fancurcuit1.jpg
http://i151.photobucket.com/albums/s150/albersondh/fan/DSC03449.jpg
http://i151.photobucket.com/albums/s150/albersondh/fan/DSC03451.jpg
http://i151.photobucket.com/albums/s150/albersondh/fan/DSC03452.jpg
http://i151.photobucket.com/albums/s150/albersondh/fan/Fanswitch.jpg
http://i151.photobucket.com/albums/s150/albersondh/fan/Fanswitch2.jpg
http://i151.photobucket.com/albums/s150/albersondh/fan/Fanswitch3.jpg