Notices
GM Engine & Exhaust Performance EFI | GEN I/GEN II/GEN III/GEN IV Engines |Small Block | Big Block |

How to put a switch in Nelson 3-Relay harness?

Thread Tools
 
Search this Thread
 
Old 07-26-2010, 09:09 PM
  #11  
TECH Resident
Thread Starter
iTrader: (8)
 
02'Z71ONDUBZ''s Avatar
 
Join Date: Feb 2009
Location: Tahlequah/Norman, OK
Posts: 797
Likes: 0
Received 0 Likes on 0 Posts
Default

Shouldnt there be a wire connecting to the relay plug that controls high for that particular fan? Why couldnt i splice those wires and run them to a 3 prong switch with hot and ground? I want to use an on-off switch with three prongs on the back. Is that possible?
Old 07-26-2010, 09:12 PM
  #12  
I have a gauge for that
iTrader: (42)
 
Atomic's Avatar
 
Join Date: Jan 2006
Location: Huntsville, AL
Posts: 16,261
Received 391 Likes on 261 Posts
Default

yea if you use diodes
Old 07-26-2010, 09:20 PM
  #13  
TECH Resident
iTrader: (7)
 
brent5631's Avatar
 
Join Date: Nov 2006
Location: Dallas
Posts: 862
Likes: 0
Received 1 Like on 1 Post
Default

Also since this is a nelson harness, Atomic would your wiring diagram work since the A/c relay is triggered off of a positive signal not a ground.
Old 07-26-2010, 09:46 PM
  #14  
I have a gauge for that
iTrader: (42)
 
Atomic's Avatar
 
Join Date: Jan 2006
Location: Huntsville, AL
Posts: 16,261
Received 391 Likes on 261 Posts
Default

Im not sure if that version connects to the pcm or not, or just the ac wire, but this should work

Old 07-26-2010, 09:52 PM
  #15  
TECH Resident
Thread Starter
iTrader: (8)
 
02'Z71ONDUBZ''s Avatar
 
Join Date: Feb 2009
Location: Tahlequah/Norman, OK
Posts: 797
Likes: 0
Received 0 Likes on 0 Posts
Default

So which relays and wires control the high stage on the fans
Old 07-26-2010, 09:53 PM
  #16  
TECH Resident
iTrader: (7)
 
brent5631's Avatar
 
Join Date: Nov 2006
Location: Dallas
Posts: 862
Likes: 0
Received 1 Like on 1 Post
Default

Yeah. I was thinking of the two pin harness at first and forgot that the A/c relay triggers positive. That new one should work.

To control High on both fans both relays have to be triggered.
Old 07-26-2010, 09:57 PM
  #17  
I have a gauge for that
iTrader: (42)
 
Atomic's Avatar
 
Join Date: Jan 2006
Location: Huntsville, AL
Posts: 16,261
Received 391 Likes on 261 Posts
Default

when its flipped up, the fans are on low, when its flipped down they come on high.

an issue with this would be you can still turn the fans on low with the engine off, by grounding the green wire. I have mine wired this was so i can run my fans to cool off my engine bay with the engine off, but to be safe to make sure you dont accidently run down your battery, you can put a relay on the green wire to only close when there is accessory power.
Old 07-26-2010, 09:57 PM
  #18  
I have a gauge for that
iTrader: (42)
 
Atomic's Avatar
 
Join Date: Jan 2006
Location: Huntsville, AL
Posts: 16,261
Received 391 Likes on 261 Posts
Default

when its flipped up, the fans are on low, when its flipped down they come on high.

an issue with this would be you can still turn the fans on low with the engine off, by grounding the green wire. I have mine wired this was so i can run my fans to cool off my engine bay with the engine off, but to be safe to make sure you dont accidently run down your battery, you can put a relay on the green wire to only close when there is accessory power.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ARC
GMT 800 & Older GM General Discussion
57
02-21-2022 10:54 AM
Go5.3tt06
GM Drivetrain & Suspension
120
09-12-2015 09:29 AM
Ammadien
New Members
1
07-22-2015 08:50 PM
ullose272
GMT 800 & Older GM General Discussion
6
07-19-2015 04:14 PM
01sierraon22s
GM Parts Classifieds
1
07-08-2015 11:26 AM



Quick Reply: How to put a switch in Nelson 3-Relay harness?



All times are GMT -5. The time now is 09:21 AM.