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That post is what spawned this email. I read it has both fans should come on, but I am seeing one only come on (driver side). Am I reading it right? BOTH fans should come on at 212?
I just had a wiring problem fixed, and the driver side fan started coming on afterwards. I believe the passenger side fan relay was blown. Which relay(s), since there are 3 of them, controls the passenger side fan?
That post is what spawned this email. I read it has both fans should come on, but I am seeing one only come on (driver side). Am I reading it right? BOTH fans should come on at 212?
I just had a wiring problem fixed, and the driver side fan started coming on afterwards. I believe the passenger side fan relay was blown. Which relay(s), since there are 3 of them, controls the passenger side fan?
relay one (low speed) powers both fans in a daisey chain. When high speed is initiated relay 2 and 3 are engaged..relay 3 provides power directly to the right fan , while relay 2 changes the path.of the ground so its not daisy chained anymore
If the right fan is not working,then the fan is bad,or the wiring to it...
Technically it woudnt be a wiring issue with the right fan,because the left one would not work either, so sounds like the right fan has failed and the wiring is intact. The left fan goes through the right one to ground, so if the left fan works not a wiring issue
relay one (low speed) powers both fans in a daisey chain. When high speed is initiated relay 2 and 3 are engaged..relay 3 provides power directly to the right fan , while relay 2 changes the path.of the ground so its not daisy chained anymore
If the right fan is not working,then the fan is bad,or the wiring to it...
Technically it woudnt be a wiring issue with the right fan,because the left one would not work either, so sounds like the right fan has failed and the wiring is intact. The left fan goes through the right one to ground, so if the left fan works not a wiring issue
So do you think replacing all 3 relays maybe a good first step? I can get them for about $20. If that doesn't work, replace the passenger side fan?
I think my driverside fan only comes one when I turn the A/C on.
I'll try to explain this the best I can. I'm going to use some symbols to explain.
We will use * as a symbol for the fan. We will use a dash dot . as a symbol for wiring. We will use - for ground, and we will use + for power.
Relay 1, ALWAYS provides power. This power goes directly to fan 1 first, then goes to fan 2, and then goes to ground. Fan 2 has its OWN ground. It is ALWAYS grounded.
So here is a symplistic wiring of it in LOW speed mode.
+...*...*...-
Both fans are wired in a daisy chain, power goes into fan 1, leaves fan 1, goes into fan 2, and goes to the ground on fan 2.
this means, while in LOW Speed mode, BOTH fans should work no matter what. This is how low speed is acheived is because the voltage is dropped due to 2 fan motors drawing off the same circuit.
in HIGH mode, relay 2 and 3 enable. Relay 2 Changes the grounding path for fan # 1, it gives it its OWN ground seperate from the 2nd fan. Relay 3 provides DIRECT power to fan 2, so it no longer needs power from fan 1.
BOTH fans should ALWAYS work in low speed mode, IF it does not, then the voltage is to low to POWER the fan and the motor in fan 2 is likely weak. When you directly powered it, you basiically was giving it FULL (power). At this point.
I am curious how the dual fans are supposed to operate?
What temp = Fan 1 turns on low? when does it go high?
A/C On = Fan 1 turns on low?
A/C off = Fan 1 turns off?
When does Fan 2 come on?
After reading this, I think you may be confused about what is really low. If you are only seeing FAN 1 turn on, but not fan 2, this would suggest you are really seeing fan 1 on high. If this is the case, there could be an issue with relay 3. Power and ground checks would need to be done while the system is forced in high mode, or you can just swap out the relay 3
If you swap relay 2 with relay 3, and relay 3 is bad, you'll reverse the working fan while the AC is on. Meaning, Fan 2 would work, but not fan 1 while on high. I'm also assuming Fan 2 = passenger, and Fan 1 = driver.
This one is on high, as you can see the light blue goes through relay 3, and is for the right fan. IF relay 3 is messed up, it'll prevent the right fan from functioning while the AC is on, "aka requesting high speed"
Good read. When you say low speed are you referring to a lowest setting on the dial correct? Would purchasing one new relay and swapping into all 3 positions be worth wile starting with relay 3?
Good read. When you say low speed are you referring to a lowest setting on the dial correct? Would purchasing one new relay and swapping into all 3 positions be worth wile starting with relay 3?
I'm not sure what dial your referring to, this is for the cooling fans.
and yes, buying 1 new one and playing swaptronics might get it, if it was only 1 relay was the issue.
Ok I'm lost then. Low speed as in vehicle speed. What controls fan speed? I thought you were talking about the hvac control panel? This is the GXP.
I believe he is talking about radiator fan speed. The HVAC controls shouldn't have anything to do with the radiator fan speed that I'm aware of, except they (fans) will kick on when you turn your a/c on.
I'm sure fan speed is dictated by the coolant temp sensor. The hotter, the more power will be spread to the fans.
Ok, so it is really controlled by the computer? In my old TPI cars there were different coolant temp sensors(240 degrees stock all the way down to about 186) available you could swap in to get the fans to turn on earlier, I guess that doesn't apply here. I never gave much thought about the fan speed or percentage as I am not into tuning so adjustment was not possible. Low speed just threw me right off lol.
Tried putting in a new relay to Fan 3, no difference. It may be a wiring issue.
Really I would say the next step is jumping the relays, or taking the covers off the relays and energizing them to see if the fans enable. Then from there we can talk about wiring, if your up for it let me know I'll give some instructions on what I would do next.
08-11-2016, 12:31 AM
Radiator Fan Timing Questions 
