Strange AUX fan circuit operation - Z32TT Type 2 w/ Feature Pack ROM

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merdahl
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Strange AUX fan circuit operation - Z32TT Type 2 w/ Feature Pack ROM

Postby merdahl » Wed Jul 19, 2017 12:37 am

I converted my Z32 clutch fan to a two-speed electric fan (the famous Ford high-flowing unit). I am using the Nissan radiator and sub relays originally for the AUX fan to energize a second set of relays wired directly to the battery using heavier gauge wire. The AUX fan has been removed. These relays are wired correctly, and work as expected when each Nissan relay is energized individually.

After setting up my fan switch flags in Nistune, I noticed low-speed operation is as expected. High-speed operation energizes both circuits, which my two-speed fan does not like.

Based on this observation, I added a third relay to de-energize my low-speed relay during high-speed mode.

Now, I get high-speed operation regardless fan flag settings.

You're probably thinking at this point, "OK, the idiot wired it up wrong", but here's where things get interesting! I also have the Conzult software, and it has a solenoid test function. Running through OFF-LOW-HIGH fan speeds gives the correct operation: Off is off, Low activates low-speed, and High activates high-speed coils in the fan.

Now I'm really stumped. I thought I knew what was going on, but something seems off. I will go back tonight and re-measure what's happening - ultimately the difference between Conzult and Nistune doesn't matter, and it will probably be a simple matter of re-thinking the relay arrangement, but it makes me wonder if the fan flag settings are fully understood.

Thanks for any help!
Mike

Eric
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Re: Strange AUX fan circuit operation - Z32TT Type 2 w/ Feature Pack ROM

Postby Eric » Sat Jul 22, 2017 7:19 pm

What are your current fan parameter settings and switch flags ?

also, is your main temp sensor working correctly ?
If the ECU suspects it has failed it will override all fan settings and just turns on the aux fan on hi-speed.

And I also regularly see people hardwire the aux fan to the AC relay in cars that are converted to a R134 AC system.
This can cause similar problems.

RomChip200
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Re: Strange AUX fan circuit operation - Z32TT Type 2 w/ Feature Pack ROM

Postby RomChip200 » Fri Jul 27, 2018 11:29 pm

Eric wrote:What are your current fan parameter settings and switch flags ?

also, is your main temp sensor working correctly ?
If the ECU suspects it has failed it will override all fan settings and just turns on the aux fan on hi-speed.

And I also regularly see people hardwire the aux fan to the AC relay in cars that are converted to a R134 AC system.
This can cause similar problems.



But he said it works fine with Conzult.

Matt
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Re: Strange AUX fan circuit operation - Z32TT Type 2 w/ Feature Pack ROM

Postby Matt » Sat Jul 28, 2018 7:21 am

There was a difference

Inside Conzult he is using 'active test' to trigger low/high fans. Similar operation for Nistune would be Operations > Consult active tests > Cooling Fans

However above he writes that inside Nistune he was setting the Nissan default 'flag setings' parameters. These adjust the conditions in which fans operate by default in the ECU.

RomChip200
Posts: 370
Joined: Mon May 11, 2009 7:58 pm
Location: FRANCE

Re: Strange AUX fan circuit operation - Z32TT Type 2 w/ Feature Pack ROM

Postby RomChip200 » Sat Jul 28, 2018 7:53 am

Ok, I would need to review my disassembly code. Too old in my mind.


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