Seat belt interlock experts, where are you?

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cruiser

cruiser

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Hi All: I have a very stock slant six powered 1974 Duster. I'm one of the few guys in the whole world who likes everything to work on my car - including the seat belt interlock system. I can start my car in park or neutral with the driver's belt unfastened. If I slide over to the middle or the right side of the front seat and don't buckle up, the car will not start. The warning buzzer goes off, and the red "SEAT BELT" light illuminates on the dashboard. As soon as I slide back into the driver's seat, the system malfunctions and allows me to start the car unbuckled. All wiring and connections under the front seat are intact and properly connected. All wiring in the cowl area is correct, and I have a good control module behind the instrument panel. Any ideas? Help!
 
Not an expert, but sounds like the belt switch is bypassed. Not sure how the actual belt switch works. There is a seat switch and a belt switch for each position. What happens if you try to start it without sitting in the car? There are several pages in the Body Service Manual just to troubleshoot this system. Also mentions this could be caused by the underhood switch
 
zkx14 said:
Not an expert, but sounds like the belt switch is bypassed. Not sure how the actual belt switch works. There is a seat switch and a belt switch for each position. What happens if you try to start it without sitting in the car? There are several pages in the Body Service Manual just to troubleshoot this system. Also mentions this could be caused by the underhood switch
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I have a set of belts out of a 74 Duster here I just looked at. Would be real easy to connect the 2 wires together right at the connector and bypass the switch... This set actually has broken wires going to what I believe is the center belt -without the heavy plastic cover. You can test the switches for continuity by unplugging the wire connector and test to the pins with and without the buckle in.
 
Get under the hood and look for the reset box. It's about the size of a horn relay with a "used to be" red reset button, likely over by the ignition box/ start relay. There are two "yellowish" wires. Connect them permanently. Now try pulling all the seat connectors. If that doesn't "kill" the noise, unplug the big box under the dash
 
67Dart273 said:
Get under the hood and look for the reset box. It's about the size of a horn relay with a "used to be" red reset button, likely over by the ignition box/ start relay. There are two "yellowish" wires. Connect them permanently. Now try pulling all the seat connectors. If that doesn't "kill" the noise, unplug the big box under the dash
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Driver seat is disabled now. He wants it all to work...:realcrazy: :poke:OP, LOL
 
did you actually remove the front seat and verify the contacts haven't been jumpered out?
 
67Dart273 said:
Get under the hood and look for the reset box. It's about the size of a horn relay with a "used to be" red reset button, likely over by the ignition box/ start relay. There are two "yellowish" wires. Connect them permanently. Now try pulling all the seat connectors. If that doesn't "kill" the noise, unplug the big box under the dash
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If I understood correctly he isn’t trying to bypass the system. He actually wants it to work properly and is annoyed that it doesn’t.
 
zkx14 said:
Driver seat is disabled now. He wants it all to work...:realcrazy: :poke:OP, LOL
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there's one in every crowd :lol:...hope you get it working...on the other hand, if you remove all of it, it won't be on your car and no longer subject to needing fixing :D
 
God i hate those seatbelts in my 74 they always tighten up and jam. Good luck
 
You need to ask yourself a serious question. "Do I want this mess of poorly designed U.S. Federal required (and then deleted) **** to cause my car to stall in busy traffic? And risk getting hit or worse by someone else who can't or won't stop or wasn't paying attention?

I would not have this mess shoved up my ***
 
Thanks everyone for the replies. Your comments about the poor design and difficulty of this system are well taken. As I mentioned, one of the things that I like about this hobby is the challenge of getting everything to work the way the factory built it. I know that's strange, but that's the way I roll and I know that most people couldn't care less about the interlock system. But I have it hooked up on my other 74 Duster and I've gotten quite used to it. Anyhow, I think I've isolated it to the driver's seat switch. This is a funny looking slide switch under the driver's seat that that senses weight in the seat and sends a signal to the system. As near as I can tell, it isn't jumpered and looks completely untouched. Sitting in the middle or right side of the front seat causes the interlock system to operate normally. Whatever is happening is happening on the driver's side. Any more ideas?
 
cruiser said:
Anyhow, I think I've isolated it to the driver's seat switch. This is a funny looking slide switch under the driver's seat that that senses weight in the seat and sends a signal to the system.
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you need to pull the seat and see if there's an old piece of seat foam or something else stuck between the contacts
 
I wonder if it might be the switch in the driver's seat belt. It's normally open, but I wonder if it may be stuck closed, leading the system to believe that it is buckled all the time. Any ideas as to how I might check it?
 
PROBLEM SOLVED. Bob here. I pulled the front seat and found one of the two leads into the driver's pressure switch had been severed. I previously inspected all of the underseat components, but this wire had been cut and the butt end stuck back into the plug so that it looked like it was still connected. So I missed that until I pulled the seat again today and got a better look at the connectors. I repaired the cut wire and the system operates normally now for the first time in three decades.
 
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