E-fans, Diablo, And Nelson

[ryaleon]

Anyone have electric fans with the nelson performance harness and diablo tuning? The fans come on fine with the temperatures set by the diablo but I cannot get the fan to come when the ac is engaged.

It's my understanding that when the ac is engaged one fan is supposed to turn on high. But it isnt.

[[__--MUD--__]]

Did you tap into the wire for the compressor clutch? There will be 12 volts on that line when the ac is running.

[ryaleon]

Originally Posted by [__--MUD--__]

Did you tap into the wire for the compressor clutch? There will be 12 volts on that line when the ac is running.

The Nelson harness instructions online said to do it like that. But the instructions i received said to wire the green wire into pin 33 instead. I called them to see which set of instructions were the correct ones, they advised the pin 33 ones were.

Which wire is for the compressor clutch? I know it's a green wire but not sure which green or where it's at. Also have read that it's a lime green wire. I have a really hard time distinguishing greens and yellows and oranges so hope its not a green.

[[__--MUD--__]]

Look at the compressor clutch... There are only a few wires running to it.

It should be Dark Green / White

I dont know what they are directing you to do, but pin 43 off C2 is the compressor. Pin 33 isn't even used.

[ryaleon]

Alright I'll go look for clutch wire. so dark green with a white stripe? They claim blue pin 42 is low speed and pin green 33 is high speed/ac pressure sensor.

[[__--MUD--__]]

Easy to verify- Jab a 12V test light at the compressor end, turn the ac on/off. Light should follow your switching. Hit pin 43, should do the same.

The line on the compressor side should be solid dark green. On the PCM side it should be dark green & white.

[[__--MUD--__]]

Full pinout-

http://www.lt1swap.com/2004vortec_pcm.htm

[ryaleon]

on the pcm side it will be in the large loom correct?

[ryaleon]

Originally Posted by [__--MUD--__]

Full pinout-

http://www.lt1swap.com/2004vortec_pcm.htm

Thanks for that I have it bookmarked now. So green 43 is the pin to use then.

[[__--MUD--__]]

****, I bet you need to have the pcm programmed for it to work as they directed you for it to control the fans.

big thread here-
http://www.performancetrucks.net/for...-432250/page4/

[ryaleon]

It is programmed with the diablo tuner. But it wont activate the fans when the ac is turned on. Only when coolant gets up to a certain temperature. I don't think diablo has the ability to tune it the way it needs to be. Only options are fan1 and fan2 temps.

[[__--MUD--__]]

I'd call nelson back to verify what we think is going on. You may have to call diablo to see if it will set a parameter for an option thats currently non-existant in the PCM.

I personally dislike these handheld tuners...There are so many people doing mail order tunes cheap- under $250. Give you full control vs the limited options on the handhelds. Depending on who you use, additional changes/re-programming could be free to $100.

Worst case your diable wont do what needs to be done, uninstall it, sell it, and get a custom tune and your good to go.

if your driving the truck, I'd temporarely hook it up to the clutch wire so you dont smoke your AC by not pulling air over the condensor.

[ryaleon]

I will call Nelson tomorrow to confirm
Just spoke with my diablo tuner and he told me he had no settings for this. I may go the HP tuner route as i know they have this option. Nelson offers the tuning i nees but its just as expensive as the hp package.

[tomp]

Get Nelson on the line for assistance in answering the question, "Does the harness support both temperature activation on Pin 42 and High Mode when AC is enabled for pin 33"? I was not aware of the harness supporting both on H2s I have seen this kit installed on int he past. If it does not support both, a seperate relay and diode will have to be installed for the AC Engagement to override the fans and increase speed from low to high.

Good luck, sounds like you are almost done...

Which fan shroud did you use? One from 2008+ H2? I am hearing this is a very good mod on older H2s with manual belt driven fans, adding about 15-25 hp and slight increase in MPG. Also gets rid of the roaring sound when running AC, as well as overheating that is a result from running AC while parked.

[ryaleon]

So for now i will tap into the ac wire. The workaround ive been using was turning fan on at 100°. Only low speed but enuff to save my ac

[ryaleon]

When I spoke to them they said it should be hooked up using both pins. 42 for low and 33 for high/ac. I used the 2500 hd shroud. For MPG no increase. The roaring sound is gone. Much better throttle response but best of all. No warm ac at idle or park. Only issue is getting pin 33 to function.

[tomp]

Can you confirm the Nelson harness has a wire to adapt to pin 33?

Have you checked pin 33 for output voltage, either using dummy light or voltmeter? If no voltage, and nelson harness has a separate wire for this to function, it's not a show stopper if diablo doesnt support it - just tap into power wire to compressor using a relay.

[ryaleon]

Yea the harness has a wire for pin 33. I haven't checked the voltage
I suspect it wont show anything until that pin is activated. So for now ill just use that wire and tap into ac line. Just hope i can find the correct wire. As i said im bad with colors.

[tomp]

Why even worry about the color when we both already know that Diablo doesn't enable it? Go directly to the AC compressor. Before doing this, determine if the Nelson harness includes the relay for it though. You surely don't want to add in the high fan circuitry current without some relay in there somewhere. If you are not comfortable doing this, any high end car stereo shop should be able to do it, just show them the wire on the harness that it should attach to and tell them to hurry up

[ryaleon]

Because I needed to know what color the ac compressor wire was.