Hi everyone,  I have a 1965 series 75 Cadillac limousine.  As you might know, the '65 limousine was a '64 carryover.  I need a neutral safety switch for my '65 limo.  Do I look for one to fit a '65 or a '64?  Also, is the NSS for a commercial chassis the same as all other Cadillacs?  This is a non-tilt, non-telescopic turbo hydromatic.  Thank you.  Jim

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The 65 series 75 NSS is the same as the 64 with a TH400 trans   The NSS is the same for all the models.

Reply by Russ Austin yesterday

The 65 series 75 NSS is the same as the 64 with a TH400 trans   The NSS is the same for all the models.

Russ, the article Jason referred to says the '65 75 series used NSS 3653.  You're saying my car uses NSS 3652.  Guess I'll have to remove what's there and hope the part number is on the NSS.  Jim

The 1965 Series 75 came with the 652 NSS. The 1965 688 Switch can be modified to use as a replacement for the 653 NSS. I updated the post to try and clarify.

By

There are details regarding the 1965 75 series #653 switch and making mods to the #688 switch used on other 1965 body styles on this Help Page linked article toward the bottom

http://6364cadillac.ning.com/profiles/blogs/neutralsafetyswitch

Mine had a chipped plastic housing. It was a 652 I believe. Was it similar damage? JB Weld, some cut styrene plastic, and some dielectric grease fixed my problem.

Why do you need a "new" NSS? Is yours lost? If not, but damaged, its most likely repairable. There is an instruction in the Help section. However, if you want the best result send it to Russ Austin and let him repair it for you.

There is also a way to remove your NSS and install a new "home made" type that will work. Believe Russ has a kit for that as well.

Once in a while there is a suitable NSS for sale on Ebay. Price is of course high as availability is limited. You will be much better off repairing yours.

Finally, the Help section is the place to go to for all your problems. And Jason is hard at work changing the layout so it will be easier to find the information.

Tony, I found it under Neutral Safety Switches from the Help Page:


Neutral Safety Switches: Function and Different Switches Used in 1963 and 1964
http://6364cadillac.ning.com/profiles/blogs/neutralsafetyswitch

It says:

Neutral Safety Switch: The engine should start in Park and Neutral Only. When in Park or Neutral the switch closed the circuit between the violet (purple) and dark blue wire.  If switch is defective these can be jumpered to bypass the NSS and crank the care. NOTE & WARNING: this means the car can then be cranked in any gear, including the drive gears!

Long story short, I had a vacuum leak from the NSS that my mechanic fixed.  But immediately after that, every time I turned the steering wheel, the horn tooted.  So he bypassed the NSS by soldering a wire somewhere.  Now the car starts in any gear, I have no horn at the steering wheel but it still toots occasionally when I turn the steering wheel.  So I really don't know what is broken at this time!  I figured I'd start with the NSS.

It sounds like your mechanic completely bypassed the NSS start and vacuum features.

Is your car a tilt or non tilt steering wheel?

Non-tilt

Updated.

RSS

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