Ac / electric fan help

Zacheus

Not-quite-so-new-guy
Sep 2, 2017
17
4
3
#1
I have a 1982 Monte Carlo cl that I installed a Holley sniper efi on been running great since December. I’m currently installing the ac back on the car and need a little help. The Holley sniper has the ability to turn my electric fans on when the ac is switched via a ground input to the efi unit. My question is can i splice into the ground connection on the ac compressor plug ?
 

ldr

Master Mechanic
Sep 16, 2016
254
190
43
Sarcoxie, MO
#2
My sniper don't have that function. It has a AC kick feature that opens the IAC a touch to help with idle rpm from compressor load.
 

454GrandPrix

Master Mechanic
Jul 27, 2016
353
462
63
Lehi, Utah
#3
The Holley sniper has the ability to turn my electric fans on when the ac is switched via a ground input to the efi unit. My question is can i splice into the ground connection on the ac compressor plug ?
Maybe, depending how the car triggers the compressor. If the car turns on the compressor by sending a ground signal, then you can tap into this same signal and send it to your EFI. If the car turns on the compressor by sending positive voltage to it, then you'll need to expend more effort. (I don't know which way it works because my A/C system is not functional.) If the latter case is how it works, you could install a relay which is triggered by the A/C voltage but then merely sends a ground signal to your EFI.

Just a thought.
 

Zacheus

Not-quite-so-new-guy
Sep 2, 2017
17
4
3
#4
I remember seeing it when messing with the software on my computer. I'm not 100% sure but I believe it's tied into the iac kick fuction which is a ground input into the sniper. So to get the iac fuction to work I would just splice a relay into the positive voltage side of the compressor and use the ground side as a input into the sniper?

Thank you for your help
 

Attachments

ldr

Master Mechanic
Sep 16, 2016
254
190
43
Sarcoxie, MO
#5
I used the 12V wire that went to the idle solenoid on the old carb. I ran it to the relay for the idle kick and to turn second fan on with ac switch.
 

Zacheus

Not-quite-so-new-guy
Sep 2, 2017
17
4
3
#7
I used the 12V wire that went to the idle solenoid on the old carb. I ran it to the relay for the idle kick and to turn second fan on with ac switch.
Thank you that's what I was thinking as well when looking at the service manual. Now I know I would run the solenoid wire to #86 on the relay and how would I wire the other termanals?
 

Zacheus

Not-quite-so-new-guy
Sep 2, 2017
17
4
3
#8
Are you using a laptop with the sniper?
I have the software but haven't really used it.. I like to play with it to better understand how to use it when needed but i have taken a couple data logs and it's very impressive
 

ldr

Master Mechanic
Sep 16, 2016
254
190
43
Sarcoxie, MO
#9
30 and 85 to ground, 87 to sniper. Set ac kick to about 5% then tweak it from there. I wouldnt change much until you get a few hundred mile on it. Honestly not sure I would even mess with the ac kick. If you set idle and IAC correctly it wont need it. I was wondering why both fans come on, on my car when I turn ac on. It s programmed that way from factory. Looks like the only way to fix that is to buy the dongle for a laptop.
 
Last edited:

Zacheus

Not-quite-so-new-guy
Sep 2, 2017
17
4
3
#10
30 and 85 to ground, 87 to sniper. Set ac kick to about 5% then tweak it from there. I wouldnt change much until you get a few hundred mile on it. Honestly not sure I would even mess with the ac kick. If you set idle and IAC correctly it wont need it. I was wondering why both fans come on, on my car when I turn ac on. It s programmed that way from factory. Looks like the only way to fix that is to buy the dongle for a laptop.
I agree and the only reason I want the iac kick feature is for the fans or will they come on with out wiring the kick?
 

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