Conversions & Swaps LSX Engines in Non-LSX Vehicles
Sponsored by:
Sponsored by:

Neutral Switch Wiring with PCM inputs

Thread Tools
 
Search this Thread
 
Old Oct 4, 2016 | 08:38 PM
  #1  
NikP's Avatar
Thread Starter
Teching In
 
Joined: Nov 2011
Posts: 11
Likes: 0
Default Neutral Switch Wiring with PCM inputs

I have a Lokar shifter which has a normally closed switch when the shifter is in P and N. As I understand it, the PCM needs ground for #32 and #34 so know that transmission is in P or N.

I know I can just connect the PCM wires to one side of the switch and the other to ground and I've accomplished what the PCM needs.

From a wiring standpoint, I also want to make sure the engine can't be started unless it's in P or N.

I assume I need a relay to keep the PCM and starter wiring separate to accomplish this task.

Can all the smart wiring guys validate my thoughts here. I think the picture should do the trick. If not, teach me the flaws in my relay and wiring understanding.


Reply
Old Oct 4, 2016 | 09:24 PM
  #2  
slocaddy's Avatar
TECH Fanatic
 
Joined: Jan 2010
Posts: 1,074
Likes: 17
From: sarasota fl
Default

What year nss do you have ? at least 04 and down, the literall starting circut does not pass through the pcm,
Reply
Old Oct 4, 2016 | 09:33 PM
  #3  
NikP's Avatar
Thread Starter
Teching In
 
Joined: Nov 2011
Posts: 11
Likes: 0
Default

2002 from a GMC Sierra truck.

I realize PCM doesn't need anything from start circuit but from what I read it does need to know if trans is in park or neutral for training on base idle etc...

I know some just leave it out but while I'm here I'd rather give the PCM what it thinks it needs.

I don't have a PRND range switch so that's why I'm trying to incorporate this way and avoid buying one since the PCM only needs to see 32 and 34 grounded in P/N.
Reply
Old Oct 4, 2016 | 11:46 PM
  #4  
ls1nova71's Avatar
TECH Veteran
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (4)
 
Joined: Jan 2008
Posts: 4,406
Likes: 211
From: Liberty, MO
Default

I assume you're going to tune it like an Fbody so you don't need the range sensor, so in that case you only need to ground pin 34, not sure where you came up with needing to do the same with 32? But your schematic shows the PCM only getting that signal during cranking , it should have the signal anytime the ignition is on and the car is in park or neutral, not just when starting it. I will draw you a schematic, but just starting work now, so give me a little time to get it posted.
Reply
Old Oct 5, 2016 | 12:56 AM
  #5  
ls1nova71's Avatar
TECH Veteran
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (4)
 
Joined: Jan 2008
Posts: 4,406
Likes: 211
From: Liberty, MO
Default

This is my thread from several years back on how I wired my wagon. Has been on the road since and works great. https://ls1tech.com/forums/conversio...-question.html
Attached Images  
Reply
Old Oct 5, 2016 | 06:44 AM
  #6  
NikP's Avatar
Thread Starter
Teching In
 
Joined: Nov 2011
Posts: 11
Likes: 0
Default

Brendan @ltswap.com said to send both 32 and 34 to ground so not sure of the full understanding of what's needed in th PCM, but he certainly knows more than me.

Thanks, makes sense now to have 12v power all time to the PCM side relay. I had it covered for the strart cycle, but wasn't thinking about the PCM during just a normal running condition where the trans might be in P / N.

That's the input I needed. Thanks.
Reply




All times are GMT -5. The time now is 03:45 PM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE