Cooling fan relays
That's a pretty clever circuit. I guess you could have three modes.
1. C1 grounded, C2 open = Fans in series (low speed)
2. C1 open, C2 grounded = Right side fan high speed, left side fan off
3. C1 grounded, C2 grounded = Fans in parallel (high speed)
But I guess the PCM only uses 1 or 3.
1. C1 grounded, C2 open = Fans in series (low speed)
2. C1 open, C2 grounded = Right side fan high speed, left side fan off
3. C1 grounded, C2 grounded = Fans in parallel (high speed)
But I guess the PCM only uses 1 or 3.
^^Yes because Relay 1 always stays on, it is the first to turn on and the last to turn off.
Here is a really simple Diagram I made to wire in the Manual Fan Switch..I made it in refrence to the F-Bodies, but it's basically the same for all of them.
Here is a really simple Diagram for the 3-Relay setup..
Here is a really simple Diagram I made to wire in the Manual Fan Switch..I made it in refrence to the F-Bodies, but it's basically the same for all of them.
Here is a really simple Diagram for the 3-Relay setup..
Last edited by the_merv; Jun 10, 2009 at 08:58 AM.
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85- neg/ground from circuit that powers the Relay to activate it.
86- + power from ign. circuit, or from where ever you want the source to activate the Relay.
30- function in for the circuit that you have the Relay for(power, ground, signal..etc).
87- function out when Relay IS energized.
87a- function out when Relay IS NOT energized.
Don't get this confused with the pic of the Fan Wiring I have posted above, that is showing it with the Relays NON energized.
85- neg/ground from circuit that powers the Relay to activate it.
86- + power from ign. circuit, or from where ever you want the source to activate the Relay.
30- function in for the circuit that you have the Relay for(power, ground, signal..etc).
87- function out when Relay IS energized.
87a- function out when Relay IS NOT energized.
Don't get this confused with the pic of the Fan Wiring I have posted above, that is showing it with the Relays NON energized.
Last edited by the_merv; May 11, 2009 at 04:01 PM.
Finally got them wired up today...
Let it idle for awhile to get temp up. Fans turned on...but stayed on low speed.
Went for a drive in this 90 degree heat...stopped a couple times to see if they were on, they were, but from the gauge in my truck they come on around 200, and stay on low.
I know I need to get my pcm changed to turn on at lower temp, but should they go to high at some point or what?
thanks merv, your diagram worked great!
Let it idle for awhile to get temp up. Fans turned on...but stayed on low speed.
Went for a drive in this 90 degree heat...stopped a couple times to see if they were on, they were, but from the gauge in my truck they come on around 200, and stay on low.
I know I need to get my pcm changed to turn on at lower temp, but should they go to high at some point or what?
thanks merv, your diagram worked great!
Ok, I thought I had figured this out, but no dice. Can someone please help me out.
I am running Nissan Altima electric fans with my swap and they are already dual speed fans. Each fan has 4 wires coming off of it and I'm not sure how I need to wire them, using the three relay setup shown above. Has anyone wire fans like these and have a diagram they can share?
I am running Nissan Altima electric fans with my swap and they are already dual speed fans. Each fan has 4 wires coming off of it and I'm not sure how I need to wire them, using the three relay setup shown above. Has anyone wire fans like these and have a diagram they can share?
How many amps are these fans drawing?
i always hear about people burning up there relays for there fans on the trucks when they use a nelson harness or similiar.
could this be because of to much current for the relay or because of people not using 3 relays like intended from the factory?
because i can get a 70amp realy but not a Single Pole Double Throw like relay 3 in mervs diagram
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i always hear about people burning up there relays for there fans on the trucks when they use a nelson harness or similiar.
could this be because of to much current for the relay or because of people not using 3 relays like intended from the factory?
because i can get a 70amp realy but not a Single Pole Double Throw like relay 3 in mervs diagram
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What code is it giving? We have to know what is causing the light to come on.
