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T-Series Plastic disk switch encased in seat bottom foam??

Blackjokr

Jedi Warrior
Offline
I took apart my 1979 front seats. Removed all of the upholstery for a complete remake using MOSS's kits, foam, etc. However, when the seat was removed, there was a 3 prong wire hangin out of the bottom of it. As I removed the vinyl, I founs a plastic disk about 5-6 inches wide attached to that wire. It had a wire coming out of it (it was detached from the car somewhere...?) and the disk was a kind of switch. If you push it, it pushes in (clicks). Any idea what this is?? I think it may have been hooked up for the seatbelt warning light or something? The foam was molded for it and it had a thin metal bottom where it was glued to the foam. If anyone know what it is please help me find replacements! I only did the drivers side so far> not sure if the passenger side has it or not. Thanks!
 
Re: Plastic disk switch encased in seat bottom foa

Both seats have 'em and they are seatbelt warning light switches.

Welcome to the forum, BTW! /ubbthreads/images/graemlins/savewave.gif
 
Re: Plastic disk switch encased in seat bottom foa

My 77 "Molly" also had the sensor for the seat belt in the seats but I had to disconnect the one on the drivers side because sitting in the seat made the ignition light come on and the car wouldn't charge. /ubbthreads/images/graemlins/driving.gif
 
Re: Plastic disk switch encased in seat bottom foa

Thank you for the welcome and quick reply DrEntropy!! ok, any idea where I cna get them?? I have catalogs from both Moss Motors and British Victoria and I do nto see either unless I am blind! Thank you!
 
Re: Plastic disk switch encased in seat bottom foa

When in question check with Tony I guess.

I supose I would just chuck em.
 
Re: Plastic disk switch encased in seat bottom foa

Yeah, Jack. Me too. I wouldn't care about 'em and besides: it's less mass... /ubbthreads/images/graemlins/devilgrin.gif
 
Re: Plastic disk switch encased in seat bottom foa

aww shucks..I kinda liked em.
 
Re: Plastic disk switch encased in seat bottom foa

Something less to fall off.
 
Re: Plastic disk switch encased in seat bottom foa

I chuck 'em....
 
Re: Plastic disk switch encased in seat bottom foa

Jack
I have some 79 seats with at least one maybe two of the switches. I think it/they work. You can have it/them if you want. Just have to pay for shipping.

Let me know if you want it. /ubbthreads/images/graemlins/grin.gif
 
Re: Plastic disk switch encased in seat bottom foa

Wouldlove em Kev! How much, and where??
 
Re: Plastic disk switch encased in seat bottom foa

This is my first post...have been slowly semi-restoring a '78 B. Also have a '54 TF that I did a frameoff restoration back in the mid-60's and own and drove MGB-GT's until my wife and I started a family in the late '70s....so MG's have been a part of my life for a long time.

I have been chasing the seat belt system on my B...and note there is just a single driver side seat cushion switch on my car. There is no wiring from the loom to connect a passenger seat switch...but that is only the beginning of the mystery. The leads from the dirver side swith connect to a pair of wires coming from the bundle behind the console (brown/purple and black). I researched the schematics for B wiring and discovered this circuit seems to go nowhere. The brown/purple and black wiring appears on the schematic in both the Haynes manual and the Bentley book... but there is no driver seat cushion switch in the circuit...one end of the pair terminates in a symbol for the typical two circuit connector...and the brown/purple wire runs apparently up to the right side of the engine compartment near the large plastic connector that joins four heavy brown wires together...the two circuits servcing the lights and the fuse block. But there is just a plain little dot at the end of the brown/purple wire on the schematic. My car actually has a small stub of the smaller guage brown wire protruding from the wiring loom where two of the larger brown wires emerge...but it has no voltage on it and certainly does not relate to a brown/purple mate through a missing line fuse.

I e-mailed the tech folks at Moss in California about this anomaly...and they did not have any information on it. Going back to the '73-'74 North American wiring schematic published in the Haynes manual, brown/purple circuitry is indeed used for a variety of functions...two seat cushion switches, the buzzer and the seat belt warning, all serviced by a brown/purple wire originating near the fuse block through a line fuse. It was all handled by a fairly complex (12 external contacts) sequential seat belt control unit. The more simplified module (6 contacts used in the later cars handles a wire from the driver's side seat belt switch...but there is no indication of a brown/purple wire in any of the circuitry related to the seat belt system. I'm having some trouble with the module functioning correctly and suspect some component failure...I've developed a schematic of the internal circuitry and am pursuing replacement components which I'll report on if I am successful.

So....after all that...was the post '73-'74 driver seat cushion switch connected to the car's electrical system at all or was it a hangover from an earlier design that just never got re-integrated into the new module design?

I would agree that ignoring this wiring and switch probably resolves any operational concerns, but from the purist's perspective, I sure am curious about what those guys in Abingdon intended.
 
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