Neutral safety switch question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

sjarrett71 · 04-16-2007, 08:14 PM

I just put a new (used) under dash harness on my 72. I'm thinking that the donor harness came off a stick shift. The reason is the new harness doesn't have the two thick purple wires that attach to the right side of the switch. I partially took apart my old harness and one of the wires goes to the fuse block and the other looks like it goes to the ignition switch. My new harness looks like it has the thick purple one on the ignition switch but not the fuse block. None of the wires on my new harness were cut either. My question is, do I need the two thick purple wires and what do they do? Does anyone have a wiring schematic for the neutral safety switch?

lbpd719 · 04-16-2007, 10:14 PM

just a thought, have you checked the wiring diagrams available here for D/L?

They may help a bit..

jhow66 · 04-16-2007, 11:03 PM

Just cut the purple wire on new (used) harness and put one end on one side of netural safety switch and the other end on the other side.(does not go to fuse panel-just looks that way.)

sjarrett71 · 04-16-2007, 11:44 PM

Is that how to bypass it? Another thread I looked at said one wire goes to the starter and the other to the ignition switch. Does that sound right? If what you're telling me bypasses it that would be fine.

GREASEMONKEY72 · 04-16-2007, 11:52 PM

its funny that i keep hearing about the NSS but yet my truck doesnt have it, cause i can move the shifter while standing outside the truck and i once started it in gear, it was in the middle of traffic and i didnt think to take it out of gear first but thats the only time i had it stall on me

jhow66 · 04-17-2007, 12:07 AM

You have a auto trans-right? If you do you will need to hook up the netural safety switch or truck will start in any gear. If that is ok with you just leave the new harness as is.

sjarrett71 · 04-17-2007, 12:12 AM

Ok, I haven't tried to start it yet because I haven't got everything put back together yet plus I have a new underhood harness I need to put on tomorrow. Thanks for the info.

sjarrett71 · 04-17-2007, 09:28 PM

Thanks for all the input. I finally just cut my old wiring harness up and took out the two thick purple wires for the neutral safety switch and put it in my new harness. And yes, it did attach at the fuse block. One wire went from the ignition switch to the neutral safety switch and the other went into the fuse block and connected through the firewall. Didn't check to see where it went out in the engine bay but I did check to see if it worked and it did.

04-16-2007, 08:14 PM	#1
sjarrett71 Registered User Join Date: Dec 2006 Location: Rolla, MO Posts: 2,463	Neutral safety switch question I just put a new (used) under dash harness on my 72. I'm thinking that the donor harness came off a stick shift. The reason is the new harness doesn't have the two thick purple wires that attach to the right side of the switch. I partially took apart my old harness and one of the wires goes to the fuse block and the other looks like it goes to the ignition switch. My new harness looks like it has the thick purple one on the ignition switch but not the fuse block. None of the wires on my new harness were cut either. My question is, do I need the two thick purple wires and what do they do? Does anyone have a wiring schematic for the neutral safety switch? __________________ -Scott-

04-16-2007, 10:14 PM	#2
lbpd719 Zappaphile! Join Date: Apr 2007 Location: Los Banos, California Posts: 228	Re: Neutral safety switch question just a thought, have you checked the wiring diagrams available here for D/L? They may help a bit.. __________________ 1969 C20 LWB Camper Special - The Beater.. 1998 Cheyenne V6 - 4/6 Drop - For The Son

04-16-2007, 11:03 PM	#3
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Re: Neutral safety switch question Just cut the purple wire on new (used) harness and put one end on one side of netural safety switch and the other end on the other side.(does not go to fuse panel-just looks that way.) __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

04-16-2007, 11:44 PM	#4
sjarrett71 Registered User Join Date: Dec 2006 Location: Rolla, MO Posts: 2,463	Re: Neutral safety switch question Is that how to bypass it? Another thread I looked at said one wire goes to the starter and the other to the ignition switch. Does that sound right? If what you're telling me bypasses it that would be fine. __________________ -Scott-

04-16-2007, 11:52 PM	#5
GREASEMONKEY72 Registered User Join Date: Aug 2006 Location: Bakersfield,CA Posts: 7,893	Re: Neutral safety switch question its funny that i keep hearing about the NSS but yet my truck doesnt have it, cause i can move the shifter while standing outside the truck and i once started it in gear, it was in the middle of traffic and i didnt think to take it out of gear first but thats the only time i had it stall on me __________________ -steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME

04-17-2007, 12:07 AM	#6
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Re: Neutral safety switch question You have a auto trans-right? If you do you will need to hook up the netural safety switch or truck will start in any gear. If that is ok with you just leave the new harness as is. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

04-17-2007, 12:12 AM	#7
sjarrett71 Registered User Join Date: Dec 2006 Location: Rolla, MO Posts: 2,463	Re: Neutral safety switch question Ok, I haven't tried to start it yet because I haven't got everything put back together yet plus I have a new underhood harness I need to put on tomorrow. Thanks for the info. __________________ -Scott-

04-17-2007, 09:28 PM	#8
sjarrett71 Registered User Join Date: Dec 2006 Location: Rolla, MO Posts: 2,463	Re: Neutral safety switch question Thanks for all the input. I finally just cut my old wiring harness up and took out the two thick purple wires for the neutral safety switch and put it in my new harness. And yes, it did attach at the fuse block. One wire went from the ignition switch to the neutral safety switch and the other went into the fuse block and connected through the firewall. Didn't check to see where it went out in the engine bay but I did check to see if it worked and it did. __________________ -Scott-



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