cooling fan wiring
05-29-2007, 10:44 PM
#1
cooling fan wiring Question for the wiring gurus out there...
I have been looking at the fan relays schematic for a 2001 SS Camaro. There are three relays. When the first relay is the only one energized, it turns on the Primary Fan, but the negative side of the fan actually runs through the third relay (5-pin). When the second relay is energized alone, both the second and third relays are energized ultimately causing the secondary fan to kick on without the primary (I don't think the computer actually ever does this. I think either the primary is on, both are on, or both are off; however, they can be on independently especially for the tuners out there). And thirdy, if the first two relays are both energized, it appears that the third relay assists in linking the two fans in series to one another (both turn on). Obviously, if no relay is energized, none are running.
My question is this...why is this done this way from GM? Could they not have accomplished the same thing with two simple relays?...energize one, that fan comes on, energize the other, the other fan comes on, energize them both, they both are on. The only difference I can see is that the GM circuit runs the fans in series, thus lowing the overall amperage flowing than if they were parallel. If two fans were run in parallel as my question asks, they would each be pulling their full loads. Is this the reason, or am I totally incorrect somewhere? It's been a while since I had a circuits class...
Thanks.
I have been looking at the fan relays schematic for a 2001 SS Camaro. There are three relays. When the first relay is the only one energized, it turns on the Primary Fan, but the negative side of the fan actually runs through the third relay (5-pin). When the second relay is energized alone, both the second and third relays are energized ultimately causing the secondary fan to kick on without the primary (I don't think the computer actually ever does this. I think either the primary is on, both are on, or both are off; however, they can be on independently especially for the tuners out there). And thirdy, if the first two relays are both energized, it appears that the third relay assists in linking the two fans in series to one another (both turn on). Obviously, if no relay is energized, none are running.
My question is this...why is this done this way from GM? Could they not have accomplished the same thing with two simple relays?...energize one, that fan comes on, energize the other, the other fan comes on, energize them both, they both are on. The only difference I can see is that the GM circuit runs the fans in series, thus lowing the overall amperage flowing than if they were parallel. If two fans were run in parallel as my question asks, they would each be pulling their full loads. Is this the reason, or am I totally incorrect somewhere? It's been a while since I had a circuits class...
Thanks.
