Seat Belt Interlock Relay, Late 74-76’ - how does it work? Options

[Superhawk996]

For those of you that despise the seatbelt / starter interlock and the horrific screeching noise the seat belt buzzer makes - let me say I understand completely. As I’ve been playing with this on the bench my wife now hates the noise just as much as I do.

This thread is going to explain how it works and how to bench test it over the coming days.




Credit is owed to @JeffBowlsby , @Bdstone914 , and @Montreal914 for providing me with donor parts that will make this thread possible.

Eventually I will post the schematic of this ridiculous conglomeration of components. I hope to eventually put the circuit in LTSpice to help verify its theoretical operation. I make no warranty as to the accuracy of the schematic - this is just me satisfying my own curiosity.



If you have no interest in my personality defects that would lead me to take on this little project; ignore this thread.

If you have a late car with an in-op system and eventually want to get it working - this thread is for you.

Toward the end I’ll share some ideas on how to get rid of or to change that horrific buzzer noise.

[ClayPerrine]

I can remember taking the seat cushion out of Betty's 74 years ago before I ripped out all that junk. It was at my parent's house, and my nephew was there talking to me. He asked about the wire coming out of the seat cushion. With a straight face, I told him "That is the sensor for the ejector seat. If I don't like someone, I can eject them from the car. This keeps it from going off if no one is in the seat." The look on his face was priceless. And when Betty offered him a ride he quickly refused.

(IMG:style_emoticons/default/happy11.gif)

This is the same kid that, at about 13 years old, was playing with my spark plug boot puller tool. It kinda looks like this:



He was holding it, clacking the ends together when he asked me "What is this thing?"

I said "It's a penis stretcher. Do you need to borrow it?"

He dropped it like it was red hot.

That same kid now has a master's degree in engineering and works for Peterbilt, so I don't think I did him any harm. (IMG:style_emoticons/default/happy11.gif)