Seat belt lightquery

[Mad4slalom]

Hi all, apologies in advancebut there may be a lot of tech queries as I am tackling a list of jobs.
my vette is a 72 , it has plastic seat belt stalks which I thought were from a later year car. I am about to fit the dual retractor lap and shoulder belts i bought a while back. I removed the passenger seat but notice a wire harness from the seat base to the to rear of the car and to a wire attached to the seat belt stalk.
my question can I use the sat belt warning lights with the older style stalks. Is the connection just an earth through the bolt to the gearbox tunnel ? In which case it should still work but the wire seems to enter half way up the plastic stalkany one have an idea ? Many thanks

 

[Mad4slalom]

Hi all, apologies in advancebut there may be a lot of tech queries as I am tackling a list of jobs.
my vette is a 72 , it has plastic seat belt stalks which I thought were from a later year car. I am about to fit the dual retractor lap and shoulder belts i bought a while back. I removed the passenger seat but notice a wire harness from the seat base to the to rear of the car and to a wire attached to the seat belt stalk.
my question can I use the sat belt warning lights with the older style stalks. Is the connection just an earth through the bolt to the gearbox tunnel ? In which case it should still work but the wire seems to enter half way up the plastic stalkany one have an idea ? Many thanks

Not a clue where the pic of the relay came from

 

[johng]

Your plastic stalks look to me as if they are from a more modern car. My 78 has metal buckles with a webbing strap (which goes inside a plastic sleeve) as in this photo.


Also, I only have the warning switch on the drivers side, it connects to the socket with 2 black leads in this photo. Not sure if a 72 is the same as this though.

 

[Mad4slalom]

Your plastic stalks look to me as if they are from a more modern car. My 78 has metal buckles with a webbing strap (which goes inside a plastic sleeve) as in this photo.

View attachment 17702
Also, I only have the warning switch on the drivers side, it connects to the socket with 2 black leads in this photo. Not sure if a 72 is the same as this though.

View attachment 17701

Thanks johng, mine has warning on both seats, i am fitting belts like yours but wondered where the wires would attach. This is the one i have removed. The replacements were from seatbelt solutions via Ck.

 

[Mad4slalom]

Thanks johng, mine has warning on both seats, i am fitting belts like yours but wondered where the wires would attach. This is the one i have removed. The replacements were from seatbelt solutions via Ck. View attachment 17720

Actually , there are no wires from the seat on the drivers side just to the stalk. Any electrical buffs have any clue as to how the retro belts shoud be wired. The assembly manual shows wiring to the lap belt retractor not to the stalk. So the PO must have rigged something up using later stalks and single retractor and 3 point belts. TiA

 

[teamzr1]

I can only take a stab on this as not enough info

I think they are using ground, and it is in series
Coming from the 3 wires out of the carpet, the black wire goes up to the latch for the seat belt
the male connector from the seat belt has some type of contact so it in series takes the black wire and make completes the circuit
I assume it is ground, that comes out as the white wire and then goes to the larger 2 pin connector
There are 2 look like yellow wires, one would go back to where every it terminates have ground used maybe for a relay to turn seat belt light off
when male end of belt is plugged in

Where the larger 2 pin connector plugs into has to be within the length of the wires with some free slack

Maybe a test is with belt connected and key on, using a meter and see if either pin of large connector is now to ground with belt not plugged in
there should be no ground and if neither shows 12 volts then a jumper of the 2 pin connector should turn the seat belt light off

Maybe the larger connector is for the seat belt of the drivers seat ?
Would make sense ?

Or I just ate too much pizza !

 

[johng]

This is how it works for a 78, probably similar on a 72.

 

[Emc]

72 seats should have a sensor in the seat between the foam and springs

 

[teamzr1]

Edited that image to try and see it better
Does not show any sensor and hazard module only looks at driver's seat belt
which is using ground in series

 

[johng]

Unfortunately my diagram is from a 78 and it seems that a 72 is somewhat different. Makes sense though to have some sort of sensor in the passenger seat, otherwise the warning would go off every time you start the car without a passenger.

 

[teamzr1]

Found more info for 1972
The system looks for the seat belt retractor which has a switch, it does not look to see if the belt is connected but rather if the retractor has been turned as the belt is pulled
The right seat looks at a sensor in seat bottom, looks for weight on seat bottom





Wiring for 1972 Vette


1 1972 owner states

"The wiring for the seat belt warning system comes off the rear wiring harness.
It connects to the under dash wire harness and then runs under the carpet and the door sill plate on the driver's side.

The wires then come across the back panel behind the seats and one runs down under each of the "black plastic covers " which are the seatbelt retractor assembly covers.
From this point there should be 2 two wire connectors.
One connector plugs into the seat belt retractor and the other goes to the seat belt warning switch.
That connector wire goes up under the seat and connects to a simple little switch assembly that is on the second spring of the seat cushion.

"Guys, I restored my seatbelt warning system on my 72 and there is only 1 seat bottom sensor, and it is on the passenger side.
Each seatbelt retractor has a connector attached to it. On the passenger side there is a split wire.
One connector goes to the seatbelt retractor and the other goes to the seat sensor, so it comes out from under the plastic cover in front.
The wires are yellow and black if I remember correctly."

So it seems the seat belt warning comes on anytime the car is started.
The driver's side seat belt must be extended to shut it off.
IF the switch in the passenger's seat senses someone is in the seat only, then THAT belt must be extended too.

 

[Mad4slalom]

I can only take a stab on this as not enough info

I think they are using ground, and it is in series
Coming from the 3 wires out of the carpet, the black wire goes up to the latch for the seat belt
the male connector from the seat belt has some type of contact so it in series takes the black wire and make completes the circuit
I assume it is ground, that comes out as the white wire and then goes to the larger 2 pin connector
There are 2 look like yellow wires, one would go back to where every it terminates have ground used maybe for a relay to turn seat belt light off
when male end of belt is plugged in

Where the larger 2 pin connector plugs into has to be within the length of the wires with some free slack

Maybe a test is with belt connected and key on, using a meter and see if either pin of large connector is now to ground with belt not plugged in
there should be no ground and if neither shows 12 volts then a jumper of the 2 pin connector should turn the seat belt light off

Maybe the larger connector is for the seat belt of the drivers seat ?
Would make sense ?

Or I just ate too much pizza !

View attachment 17723

Thanks for that info, I will try to digest it later, ghere seems to be some kind of pressure switch under the foam of the passenger seat but not the driver’s

Edited that image to try and see it better
Does not show any sensor and hazard module only looks at driver's seat belt
which is using ground in series

View attachment 17727

Found more info for 1972
The system looks for the seat belt retractor which has a switch, it does not look to see if the belt is connected but rather if the retractor has been turned as the belt is pulled
The right seat looks at a sensor in seat bottom, looks for weight on seat bottom

View attachment 17729

View attachment 17728

Wiring for 1972 Vette

View attachment 17730
1 1972 owner states

"The wiring for the seat belt warning system comes off the rear wiring harness.
It connects to the under dash wire harness and then runs under the carpet and the door sill plate on the driver's side.

The wires then come across the back panel behind the seats and one runs down under each of the "black plastic covers " which are the seatbelt retractor assembly covers.
From this point there should be 2 two wire connectors.
One connector plugs into the seat belt retractor and the other goes to the seat belt warning switch.
That connector wire goes up under the seat and connects to a simple little switch assembly that is on the second spring of the seat cushion.

"Guys, I restored my seatbelt warning system on my 72 and there is only 1 seat bottom sensor, and it is on the passenger side.
Each seatbelt retractor has a connector attached to it. On the passenger side there is a split wire.
One connector goes to the seatbelt retractor and the other goes to the seat sensor, so it comes out from under the plastic cover in front.
The wires are yellow and black if I remember correctly."

So it seems the seat belt warning comes on anytime the car is started.
The driver's side seat belt must be extended to shut it off.
IF the switch in the passenger's seat senses someone is in the seat only, then THAT belt must be extended too.

thanks for spending time in this , all of you guysI only have the sensor in the foam of the passenger seat. The repro retractors from seatbelt solutions dont seem to have a connector on. As I say , the later seatbelts that were fitted have wiring to the stalk (2 thin black wires) that disappear up into the mechanism. Am I best not to reconnect any of the plugs and sockets yet and just not use the light function or could that possibly disable other warning lamps too ? thank to all again.

 

[teamzr1]

It looks like there was seat belt changes from early 1972s and later 72s
What is your VIN # ?
Here is a guy with early 72 and when his light also would not go off

I'd like to know if anyone knows the GM part number of the timer relay that controls shutting off the Seat Belt Warning light on early1972 built cars, AND where exactly is it located?
Mine was built Nov 9,1971, serial# 506916, and I'm trying to restore her back to original working condition, but my Seatbelt light stays on constantly.
I have taken the interior out and there was no wiring at all going to the seats or seatbelts
SO I definitely have the early 72 version of the seatbelt warning system(meaning somewhere there's a timer that after 15 seconds turns off the seatbelt warning lamp). Plus I don't know what it looks like nor can I find where this timer was located?

I did find relay 3996297 bolted ONTO THE TOP PART OF THE DASH, behind the instrument cluster towards the center(see pic below), which apparently is part of the TCS system, AND SINCE it's got so many wires attached to it, is it possible that the seat belt timer function might be part of the 3996297 relay. And my relay is shot??
Several of the TCS items were disconnected(relay on intake manifold, temp sensor wire not connected to sensor in passenger side block, etc.) so I don't know if this relay works. Or is the seatbelt timer a separate timer/relay device by itself?

So if you have an early 72, and it had this timer, and it is what turns the light off, possible you have the same issue as to that time/relay ?

 

[teamzr1]

Here is an image of early 72 where timer/relay is ( this is not stock one, owner used another type to fix)
If something wrong with it then light will never come off

 

[teamzr1]

You can see the difference when looking at 1973 then there were seat belt retractors that are wired to system

 

[Mad4slalom]

72 seats should have a sensor in the seat between the foam and springs

Mine has but just on passenger side. Got the park brake handle sorted thanks Gavin, thanks for your help and patience exlaining things.
Seat belt job going well , just the electric to sort. I know it all worked before so not the relay/timer, it is knowng where to connect the wires that used to go to the stalks

 

[Mad4slalom]

I can only take a stab on this as not enough info

I think they are using ground, and it is in series
Coming from the 3 wires out of the carpet, the black wire goes up to the latch for the seat belt
the male connector from the seat belt has some type of contact so it in series takes the black wire and make completes the circuit
I assume it is ground, that comes out as the white wire and then goes to the larger 2 pin connector
There are 2 look like yellow wires, one would go back to where every it terminates have ground used maybe for a relay to turn seat belt light off
when male end of belt is plugged in

Where the larger 2 pin connector plugs into has to be within the length of the wires with some free slack

Maybe a test is with belt connected and key on, using a meter and see if either pin of large connector is now to ground with belt not plugged in
there should be no ground and if neither shows 12 volts then a jumper of the 2 pin connector should turn the seat belt light off

Maybe the larger connector is for the seat belt of the drivers seat ?
Would make sense ?

Or I just ate too much pizza !

View attachment 17723

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