Seat belt light/switch question

[djsroknrol]

The FSB light came on over the weekend and never went out. Today I dug out the FSM and the electrical supplement trying to find the location of the seat belt switch to trace the constant on. There is a mention of the seat belt switch, but there are no pics or references to where it might be. ad

Does the '84 have a sensor under the seat, is it in the convenience tray behind the dash or is it part of the seat buckle?

 

[boomdriver]

hmmmm

interesting question.
I have not dug into that circuit but should...mine comes on sometimes in the middle of the hiway at 55 mph for no reason.

I DO know that mine has a wire from the floor harness that runs to the female part of the seatbelt latch or its mount. I'm assuming that is the contact point.
I'll see if I can find something more in the FSM and post it later when I get a chance.

 

[djsroknrol]

Thanks boomdriver...I looked for a couple of hours yesterday and couldn't find anything anywhere.

Sometimes the FSM is worth its weight in gold and other times, it's not worth lighting the BBQ with...:L

EDIT: In my '84 FSM, 8B-2 talks about the seat belt warning system in depth, but no mention of the seat belt switch. In the electrical supplement, 8A-58 shows the schematic, including the seat belt switch but doesn't give its location at the end of the section. This morning I also realized that my buzzer hasn't worked in a while...Hmmm, maybe bad timer/buzzer?

 

[djsroknrol]

Here's the schematic....

 

[boomdriver]

Yep..

In my FSM the seat belt switch IS the buckle....in the reciever portion of the buckle, inside that hard plastic boot thats mounted to the floor and rises to your right, has a 2 wire plug at the lower end at the floor. That splits off the harness that also contains the power seat wiring.

The system is operated or managed by the driver seat buckle and/or the ratcheting assy. One or the other has the switch thats like everything else on a C4....a simple ground path completion...or open. Its an 8 second timer that operates the dash lite and chime but not linked together, as in the belt gets connected the chime stops but the lite stays the full 8 seconds.

I know that my chime was sounding a little tired recently when I had the dash pad off and unplugged it briefly as I was wiping the dust out of that area of the dash sub-assy. More like a sick bird chirp...I think its about time for a new one. Heck, It may be something that can be repaired...I don;t know...never messed with one before. Since wearing the seatbelt is 2nd nature now, its not necessary but I'd like everything to work as it is supposed to.

I remember 30 yrs ago we all worked at ways to avoid a seatbelt. Besides lying to ourselves and demonstrating our ignorance and dislike of authority, its shocking to look back and remember how much energy we'd put into defeating something that was so simple and easy to deal with....we'd take the dash apart, jump wires, cut off belt clips off wrecked cars to stick in out buckle so the chime or buzzer would stop, sit on buckled belts? :eyerole(THAT was the dumbest thing I EVER saw) and go thru all sorts of gyrations to avoid placing that belt across our dacron/polyester blend shirt...:ugh As I was saying, I was a dumb SOB when I was a kid.

 

[djsroknrol]

So I had a few minutes before work to look at the belt buckle area but didn't see anything in the way of wires coming out of the base of the plastic covering/stiffener for the belt buckle. I guess I'll have to get under the carpet and see for sure; that will have to wait until the weekend. I also want to pull the reel cover to take a look see inside for a switch....at least its been narrowed down to it's not a seat sensor...

50 years ago, I bounced around in the back of a Plymouth station wagon from New York to Florida without a seat belt and suffered no ill effects.....today, with the "caution-contents is hot" mentality of drivers out there, yacking on cells, texting, watching TV, etc., etc, I wouldn't dare go out on the road without my seat belt on.

 

[djsroknrol]

I looked at the belt buckle this morning and I think the contacts (looks like 3) inside the buckle are bent so as to not make contact, especially the bottom 2. I'm going to try to jump out the buzzer and see what that does....too bad you can't find these parts anymore

 

[boomdriver]

I looked at the belt buckle this morning and I think the contacts (looks like 3) inside the buckle are bent so as to not make contact, especially the bottom 2. I'm going to try to jump out the buzzer and see what that does....too bad you can't find these parts anymore

Sure you can..

if the catalog stors have not got the after-market OEM contract ( there IS legal reason WHY many parts are not available yet) then there is a quality salvage store that WILL have it. Search FleaBay. I have bought MANY salvage parts...went to a bone yard and stripped a car myself last yr to get a collection of misc parts....as long as the piece is in good shape, its no different than the one that comes off of your car.
The Corvette used part industry is a LOT more credible than other junk yards....its smaller, caters to a specific group,. they ALL know each other, and everybody knows them. There are few stories of a customer getting burned on used parts. There are more tales of people getting screwed on after market NON-OEM stuff like bolt-on performance junk than used OEM parts.

Shop around....you can find one. Cheap I'd bet. Bunches of sellers on FleaBay.. for C4 parts.

 

[AV8R]

My 1990 coupe's seat belt lamp is now on all the time and I don't hear a buzzer.
Any detailed helps will be much appreciated. The schematic is good, but I have no idea where to look for these.

Some questions:
Where is the buzzer located?

Is the seat belt "sensor" just the make or break connection switch inside the female (right of the driver seat) seat belt receptacle?

Does the DIC panel (have anything to do with the seat belt warning light or wiring)?

 

[Schrade]

This is GM Parts Schematic - NO ELECTRONICS / SWITCHES INDICATED however.

Will check other sections of GM Parts Manual, or FSM ('90) Will take a while to flip through here...

 

[Schrade]

Some more from GM Part manual C4...

 

[vigman]

Schrade.. I beg to differ

The switch is internal of the female seat belt receiver.....

Notice the wires...
C4 Corvette Grey Seat Belts Complete 96 95 94 93 92 91 | eBay
and
http://www.ebay.com/itm/Corvette-C4...Parts_Accessories&hash=item51a49ae021&vxp=mtr

 

[Schrade]

That puts you in GOOD company vig!!! (discovered an error by GM) (but as far as that schematic, IS a switch indicated? ) (IF a switch IS indicated in that schematic, I'm listening)

I found 2 in '94 FSM - one for headlight wiring color, and another error that I cannot remember...

And somebody's stuff on eBay surely shows that GM made another error in the GM Y-Body Parts Manual for C4 - '84-'96... (I don't know who the seller is, on eBay, and I did once see a swiss cheese sandwich on eBay with Jesus' smiling on it, on eBay, so I wouldn't doubt anything I saw on eBay FOR SURE ).

I'm quad-driple checking the schematic there vig, and NO switch is indicated. If there IS one, it is NOT indicated, as I said, IN THE SCHEMATIC.

 

[vigman]

Schrade YES there is Jesus in grilled cheese

And there is a switch shown in the schematic ( " seat belt switch" ) that ties to gnd I believe when buckle is out..
I also believe it was drivers seat only ( but not 100% sure on that ,since I sold my 88 ) ...
This is typical GM for Camaro's & Firebirds as well...
I see the wire & connector as #1 in the parts list...of your last post ( tied to the seat belt receiver )

I posted 2 E bay links just to show it... I KNOW it's there on the D/S

Schematic A8-58 as shown above, 4th post

http://www.whiteracingproducts.com/images/12521667.jpg
( off your ZR-1 )

And to the OP... easy test... move seat full fwd...dig down to the seat belt base , on tranny tunnel side there will be a 2 pin connector near where the belt bolts to the body...
Un plug it jump it ( on the wiring harness side ) and see if the buzzer buzzes ( or dinger dings ) ...
Sometimes a penny, or other junk gets in the reciever keeping it from opening that gnd and the buzzer hangs on for as long as the heater takes to open the switch in the buzzer module.

Here's how it works...( to the best of memory )
Power goes to one side of the " heater " ( think turn signal flasher ) ALL THE TIME ( in Start or run ) and has ground all the time so any time the key is on the heater heats.
The light which also ties to ground all the time BUT gets power from the SWITCH portion of the heater.. so when the heater gets HOT the switch opens.

The switch in the receiver ( normally closed ) ... ties ground to the buzzer
If the seat belt is not latched ( switch closed ) the buzzer buzzes ( or goes ding ding )

The heater draws a small amount of current and after X seconds the Bi metal in the switch opens ( and stays open ) and the light & buzzer goes out...
IF the seat belt is latched.. the circuit opens for the buzzer. The heater only gets power when your in start or run..

Kinda crude

Note if you remove the jumper.. and the buzzer keeps dinging after X minutes... the heater in the module is broken ( open )

 

[AV8R]

I tried to see if there was a coin in the buckle already, but didn't see anything. I'll try maybe to remove the whole thing so I can tip it upside down or use a light to look into it deeper. Will also try the cable jumper test. Good idea!

So is the seatbelt lamp circuit independent of the DIC or ECM or CCM? That is to say we cannot clear the stuck light on state via the computer, correct? I say this because code 12 indicates the seatbelt status.


EDIT
The DIC not being plugged in when there was power caused the seatbelt and inflate lights to come on the DIC when the DIC was plugged back in.
Apparently one of the computers sensed that the DIC was unplugged and posted these two status lights to come on and couldn't be reset with power alone.
A procedure had to be done documented elsewhere on this site that cleared these lights. It was the combo of the two that was unique and wasn't just a bad SeatBelt circuit.

 

[vigman]

Av8r

Your setup is completely different.. BUT the seat belt switch is the same....

 

[AV8R]

Ive also read that for cars with power seats (as I do) there are two connectors, one larger than the other. The smaller one is the seatbelt warning cable. So that would likey be the one I want to do the jumper test with.

Have you seen threads on the forum here that indicate that the CCM can clear some of these INF REST plus SeatBelt lamp situations?
This may have tripped when I plugged in the replacement DIC panel, because thats when I believe this started. Taking power off the car doesn't solve/reset this. Theres procedures to reset these codes, not that Ive ever tried such a thing. So there may be mechanical/electrical causes and then computer code ones as well.

http://www.corvetteactioncenter.com/forums/c4-technical-performance/23545-`90-seat-belt-light.html
Bought the Air Bag Reset Tool from Mid America and both seatbelt and INFL RST lights work fine no. Took all of a minute to do

http://www.corvetteactioncenter.com/forums/c4-technical-performance/25369-seat-belt-light.html
I have already tried cleaning the sensors and resetting the computer. I even bought the midamerica tool which makes it a little easier. The one think I found in the directions which differs from the posts I read was to ground for 3 seconds, then open for 3 sec., then ground for 10. Then wait for code 12 then turn off key and disc. tool. The light will stay off for a week and then relight.

 

[vigman]

I have a 90 FSM

IF I have time tonight I'll do a bit of research....
My hands on experience stops ~ 1990.. and have never had to deal with a seat belt issue....

 

[Schrade]

If you disconnect any circuit in the SIR, then turn on the ignition, you'll get an SIR Warning light. I don't believe you can reset it without dealer's computer.




vig - I don't see text "seat belt switch" in any of the 10 parts' descriptions'.

#4 SEALING STRIP, F/SEAT ANC (buzzer announce? announcer? announcement? ANCHOR???).

I think I've seen an electrical connector in others I've owned. And the schematic says nothing about it - that I see.............)

And there is a switch shown in the schematic ( " seat belt switch" )

...

 

[Schrade]

yes I saw those on EBay, and I'm looking for a service manual diagram or picture of where this buzzer module is within the 90's console.

The key in the ignition alarm works, and I think it's the same buzzer as with the seatbelt; its just that it doesn't chime for the unbuckled case.

Pt #42, 4rth page, of the 4-page schematic that I posted, shows ALARM, Seat Belt, Ig Key, and Lamps.