Sequencing Module - C3 Seat Belt System

[Lee S.]

What is the physical location of the Sequencing Module in the car? I've searched for hours and can't figure it out. The previous owner provided it with the car when I bought it. I'm not sure if its good or bad. I want to give it a try and see it it works.

[Joe L.]

Re: Sequencing Module - C3 Seat Belt System

Lee-----

A question like this requires more information than just the fact that the car is a C3. The YEAR MODEL is important.

[Joe L.]

Addendum

Lee------

Also, what is the GM part number of the module that you received with the car?

[Lee S.]

Re: Addendum- Sequencing Module - C3 Seat Belt Sys

Sorry Joe... I've made so many postings lately I just overlooked the key information.

The car is a 1974 Coupe with 454 and Automatic. The Sequencing Module has Part # 9736651 printed on the housing.

Searching on a few different key words, I was able to come up with some other postings in the archives. I still don't know the physical location. I had the entire interior and dash out of this car 1 1/2 years ago and I don't recall seeing two non-attached large connectors.

I don't think the outlook here is very good. Closer examonation of the module reveals a lot of corrosion on the 10 point pin connector. One pin is completely missing.

Now this is just a matter of curiosity. I'm just going to take the hit on the points.

[Joe L.]

Re: Addendum- Sequencing Module - C3 Seat Belt Sys

Lee-----

I figured that you were probably referring to a 1974 but I wanted to be sure since the term "sequencing module" is not the GM term for the part that you're referring to. GM's term for the 9736651 module is "ignition interlock system logic". This device is one of three primary functional components of the idiotic, government-mandated seat belt interlock system used exclusively for the 1974 model year and, perhaps, VERY early 1975. The other components were an underhood, firewall mounted override relay, and sensors mounted under the cushion of each seat. For 1975, the government regulations requiring the device were eliminated and the interlock system was, mercifully, relegated to history.

Anyway, the "logic" module is located in the storage compartment behind the seats. As I recall, it's located in the driver's side rear fenderwell area, underneath the carpet. However, it might also be in bottom of the center or right side compartments or on one side or other of the "vertical" bulkhead seperating the passenger and storage compartments. Corrosion is a common problem for these units.

The GM #9736651 module is long-since discontinued. However, they are not too difficult to find in NOS or good used form if one looks around a bit. The same module was used for most other 1974 GM cars and some of these had the module located in places not so susceptible to corrosion. Hardly any of these were ever replaced in SERVICE (most folks just disabled the system and could care less about replacing any "modules" or other parts of the system). So, the GMSPO SERVICE inventory of system parts undoubtedly proved to be "slow sellers", I'm sure, and "languished" in GMSPO warehouses and dealer parts shelves. These often show up for sale on eBay and at swap meets.

My recommendation: disable this ludicrous system, be grateful it's gone, and thank the judges if they deduct points for its absence.

[William C.]

Re: Addendum- Sequencing Module - C3 Seat Belt Sys

The same units in passenger cars were generally mounted under the driver's seat. Any unit from a '74 GM car will work. The two seater cars are where we sent some that had faulty logic when used with three seat configurations. We processed 100% of the '74 GM production thru a testing process I ran back then. That was a wild deal!

[Lee S.]

Re: Addendum- Sequencing Module - C3 Seat Belt Sys

Thanks to all. I'm going to follow the advice of many and not attempt any more work here. As far as points go, I just offset the loss on this by getting the trip odometer working.

Thanks again.

[Craig S.]

Re: Addendum- Sequencing Module - C3 Seat Belt Sys

I disconnected this on my 74 when I bought it back in 77. As I recall, if you set a box on the passenger seat, and didn't "fasten" the seat belt around the box, the car would not start.......pretty cool huh? Craig