Cooling fan.

[slamdbusa]

Which fan is the main cooling fan on the ecu?

Is it No. 1 or No. 2?

I know the Q45 didn't use a fan controlled by the ECU, but it has spots in it for them though. I would like to know which is the one I need to use.

Thanks

[mtcookson]

but it has spots in it for them though

Now that is interesting... I would be very interested in knowing this as well so that I don't have to screw with an aftermarket fan controller.

[tmorgan4]

Check out page 10 of the EC section. It's interesting that it shows both USA and Canadian models which are different. The motor diagrams are different. The USA model has two positive inputs and two grounds, while the Canadian model has one of each.

If you were putting in an after-market electric fan, it seems like you could use either signal to turn on the relay.

[Q45tech]

1994 and later US Q uses CONDENSER pusher fan under control of ecu [aux cooling].

[qship96]

1994 and later US Q uses evaporator fan under control of ecu [aux cooling].

You do mean "Condensor" fan, dont you?

[slamdbusa]

I have mine wired to the No. 1 fan, and It doesn't seem to do squat.

Is it a ground trigger, or a power trigger?

[mtcookson]

Going by the wiring diagram definitely a ground trigger from the ECU. What kind of fan(s) are you using?

Looking at how its setup they work it just like the 3rd gen Maxima (and I'm sure other gens and cars). They use two speed fans in the Maxima and turn on one relay for low speed and both relays for high speed.

As in the FSM for the Q, the low speed only occurs when temps are between 203° F and 221°, the car is below 25 MPH, and the A/C is on. In this case relay 1 turns on.

Above 25 MPH and 221° with the A/C on, the fan(s) is on high speed (both relays on).

At any speed if the temp is above 221° and the A/C is off, both relays turn on for high speed.

Now... if you have a regular one speed electric fan I would just hook up both relays to it. This way, no matter what the scenario, the fan will turn on when the ECU tells it to.

[T45]

I think they only added the ECU fan control in later 94+? models. My 92 ECU doesn't have this control and the fans were controlled by the thermoswitch in the radiator itself. I just took out the switch and adapted it to fit my Z radiator in the drain spigot.

[mtcookson]

I was thinking that might be the case, I want to see if the earlier ECU's still have the output for it though, that would be awesome.

[Q45tech]

Important to remember that ecu starts summer protective anti overheat ignition retard when coolant temp sensor exceeds [194.9F and 199.9F different years]....................1 degree retard per 5F above optimum [to a max of 5 full degrees retard] so make sure coolant never exceeds 194-199F depending.

[T45]

My switch closed at 190 on the first stage and over 200 for the second. I didn't really care about the 2nd stage so I didn't push it.

It's funny the looks and comments one gets whilst boiling car parts on the kitchen stove...

[Carl H]

i'd imagine the ecu has output for the fan relays, ecu triggers a ground which triggers the relays.

[T45]

Only on the later ecu's. Early ones didn't use that yet, they used the thermoswitch and a/c switches for fan control. Depends on your year, I believe it to be 94 and later.

Speaking of controlling the fan, I just stumbled across this adapter that should work just fine with a tswitch.

http://www.conceptzperformance...116.8