mechanical interlock or neutral safety switch?
January 5th, 2014, 12:13 AM
#1
Registered User
Thread Starter
Join Date: May 2012
Location: Wisconsin
Posts: 26
mechanical interlock or neutral safety switch?
I have a 67 Cutlass 4dr sedan and I am trying to figure out if I have mechanical interlock or neutral safety switch because I want to convert to a floor shifter and need to know what to do depending on which one I have.
January 5th, 2014, 01:04 AM
#2
Registered User
Join Date: Apr 2013
Location: Grass Valley Ca
Posts: 973
Neutral safety switch,it's on the column,if you're talking about the shifter lock rod with floor shifter that came later not sure what year but it's with ign key in column 70' or 71'.
January 5th, 2014, 05:21 AM
#3
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,254
GM used the electrical neutral safety switch until the late 1970s. After that GM changed to a mechanical interlock in the steering column that will not allow the key to turn unless the shifter is in PARK or NEUTRAL. Since your 67 doesn't even have the key on the steering column, you obviously have an electric NSS.
January 5th, 2014, 05:47 AM
#4
Registered User
Join Date: Dec 2011
Posts: 7,286
So, all you need to do is make sure your floor shifter has the NSS, procure the extension harness, and plug it in.
You will not have the complications of the 1969+ (backdrive) linkage which connected shifter position to ignition and vice versa and locks the steering unless the key is in place and turned.
Last edited by Octania; January 5th, 2014 at 05:56 AM.
January 5th, 2014, 08:59 AM
#5
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,254
Let me clarify some possible confusion in this thread.
The OP is asking about installing an aftermarket floor shifter (per his other thread). The aftermarket instructions are asking if the car uses an electric NSS or a mechanical blocking mechanism. This has nothing to do with the column-mounted key switch nor with the backdrive linkage. The question concerns whether or not the car uses an electric NSS in the starter circuit or not. As I noted above, starting with the redesigned 1977 full size cars (and progressing to the A/G-body cars with the 1978 redesign), GM stopped using an electric NSS in the starter circuit and instead used a mechanical blocking linkage in the steering column. These cars still have a switch on the steering column that LOOKS like an NSS, but it is not wired to the starting circuit. This switch is only used for the backup lights, and on the 1981-up CCC cars it also serves as the PARK/NEUTRAL switch for the ECU. On these later cars you can pull all the wires off the switch and the car will still crank and start.
The reason why the aftermarket shifter instructions care about this is that if the car uses a mechanical blocking linkage, then obviously you don't need to worry about hooking up an NSS. Of course, since the OP's car is a 67, it DOES use an NSS.
The OP is asking about installing an aftermarket floor shifter (per his other thread). The aftermarket instructions are asking if the car uses an electric NSS or a mechanical blocking mechanism. This has nothing to do with the column-mounted key switch nor with the backdrive linkage. The question concerns whether or not the car uses an electric NSS in the starter circuit or not. As I noted above, starting with the redesigned 1977 full size cars (and progressing to the A/G-body cars with the 1978 redesign), GM stopped using an electric NSS in the starter circuit and instead used a mechanical blocking linkage in the steering column. These cars still have a switch on the steering column that LOOKS like an NSS, but it is not wired to the starting circuit. This switch is only used for the backup lights, and on the 1981-up CCC cars it also serves as the PARK/NEUTRAL switch for the ECU. On these later cars you can pull all the wires off the switch and the car will still crank and start.
The reason why the aftermarket shifter instructions care about this is that if the car uses a mechanical blocking linkage, then obviously you don't need to worry about hooking up an NSS. Of course, since the OP's car is a 67, it DOES use an NSS.
January 5th, 2014, 11:36 AM
#7
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,254
Correct. Later years used the NSS wiring on the clutch safety switch, but that was not required for 67.
January 6th, 2014, 11:09 AM
#9
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,254
January 6th, 2014, 11:24 AM
#10
Registered User
Join Date: Dec 2011
Posts: 7,286
Thx for that confusion clearing Joe, that is not at all what I got from the question, was not aware of another thread.
4door67- I assume we are talking auto trans here.
You guys with 1967 MT cars, go ahead and hit the starter with the car in gear, nothing to prevent the car taking off in gear... sheesh. Not even a clutch switch.
Sounds like an interesting project. Are you removing the PRNDL part of the dash and/or the column shift lever and collar so it appears to be a factory floor shift? Buckets or std issue 4dr bench seat??
You should be able to hook your floor shifter's NSS into the two large purple wires at your steering column, and your shifter's backup lights wiring contacts to the green or greenish small wires at the column's NSS and have both functions easily.
4door67- I assume we are talking auto trans here.
You guys with 1967 MT cars, go ahead and hit the starter with the car in gear, nothing to prevent the car taking off in gear... sheesh. Not even a clutch switch.
Sounds like an interesting project. Are you removing the PRNDL part of the dash and/or the column shift lever and collar so it appears to be a factory floor shift? Buckets or std issue 4dr bench seat??
You should be able to hook your floor shifter's NSS into the two large purple wires at your steering column, and your shifter's backup lights wiring contacts to the green or greenish small wires at the column's NSS and have both functions easily.
January 7th, 2014, 02:03 PM
#11
Registered User
Thread Starter
Join Date: May 2012
Location: Wisconsin
Posts: 26
Thx for that confusion clearing Joe, that is not at all what I got from the question, was not aware of another thread.
4door67- I assume we are talking auto trans here.
You guys with 1967 MT cars, go ahead and hit the starter with the car in gear, nothing to prevent the car taking off in gear... sheesh. Not even a clutch switch.
Sounds like an interesting project. Are you removing the PRNDL part of the dash and/or the column shift lever and collar so it appears to be a factory floor shift? Buckets or std issue 4dr bench seat??
You should be able to hook your floor shifter's NSS into the two large purple wires at your steering column, and your shifter's backup lights wiring contacts to the green or greenish small wires at the column's NSS and have both functions easily.
4door67- I assume we are talking auto trans here.
You guys with 1967 MT cars, go ahead and hit the starter with the car in gear, nothing to prevent the car taking off in gear... sheesh. Not even a clutch switch.
Sounds like an interesting project. Are you removing the PRNDL part of the dash and/or the column shift lever and collar so it appears to be a factory floor shift? Buckets or std issue 4dr bench seat??
You should be able to hook your floor shifter's NSS into the two large purple wires at your steering column, and your shifter's backup lights wiring contacts to the green or greenish small wires at the column's NSS and have both functions easily.
Thread
Thread Starter
Forum
Replies
Last Post
oldspackrat
Parts For Sale
2
November 17th, 2014 06:31 AM
