1975 Buick automatic power door lock module

[Philippe Racicot]

I've been searching for the power door lock control module for my 1975 Electra for quite some time. Mine has gone bad and it won't unlock the doors anymore. The relays are fine. 
 

Here's a picture of it. The module is located in a plastic box attached to the wiring behind the glove box. It was available as an option on the Electra and Riviera models. Cadillac offered similar modules a year later but they don't interchange. Not all cars that have power door locks have it, it was a separate option. If you have parts cars, look for a black plastic box with two relays taped to it, it looks almost like it was an add on but it's a factory option. 

[NailheadBob]

Maybe this may help, from 1975 Buick Chassis and Body parts catalog (effective April 1983) 

 

Group #13.090U Harness, electric door lock wiring       part #8915727 Harness, auto. elect.dr. locks (incl. logic box & relays)  BUT no logic box or relays for electric door locks that I could find.

 

Maybe you could only get this part (logic box with relays) in 1975 with the wiring harness?

 

 

From 1976-1977 Buick Chassis and Body parts catalog (Effective June 1977)       They do show Logic module and relay for body wiring harness (for C, E w/auto. dr. lock)

 

Group #13.095 Circuit breaker-logic module-relay, body wiring/     Relay  part #8917266 C, E w/auto. dr. lock (1976 my)

 

AND Logic module part #8917247  C, E w/auto. dr. lock (76 & 77 my)

 

Have you checked all circuits on your module #8917246-C with a OHM meter?

 

I don't see any burnt/separated spots on the circuits BUT possible solder break (poor contact OR maybe got to hot and melted a little) 3rd terminal from left on second row of 7 terminals (Maybe re-solder if that is a break in contact) I don't see any reason this could not work from the photo I see.

 

Have you checked all wiring inputs from your service manual wiring diagram to this module?

 

 

If you would like you could ship me your logic module and I could inspect and test it for you, just pay the shipping both ways.

 

Here is another source for a replacement part:   car-part.com    and add all your car information and then fill out a request form and they will contact you about the part you need.

 

I hope this may help 

 

Bob

 

 

Edited March 21 by NailheadBob
update (see edit history)

[Philippe Racicot]

I checked circuits and I have tried ordering replacement ICs but these didn't work at all. I damaged the traces as I've tried many times and I just reinstalled the original Sprague IC (I've added a quick connector). At least the original IC still locks the doors (quite annoying that it doesn't unlock them so I left it disconnected for the last 7 years!). I'd like to have another circuit board rather than attempting to fix mine again!
 

It looks like not a lot of junkyards are looking at removing these parts. Also, it's an option that was ordered on less than 10% of the cars on which it was available. 
I'll search for the 1976 part too with the part numbers you provided me. 

[Bloo]

There are some Sprague IC catalogs on Internet Archive. One of the type of chips they manufactured were "relay drivers". These mostly consist of 4 logic gates driving 4 transistors. Logic gates and pinouts vary. Unfortunately the part number on that chip 8917242C appears to be custom (not a Sprague part number). It would open all sorts of possibilities if we knew exactly what was inside the chip. I imagine you have already seen these catalogs, but here they are just in case you haven't.

 

1972: https://ia801701.us.archive.org/27/items/sprague/sprague.pdf

 

1982: https://ia800608.us.archive.org/7/items/bitsavers_spraguedatagueIntegratedCircuits_67590575/1982_IND502_Sprague_Integrated_Circuits.pdf

 

 

 

[NailheadBob]

Could you post photo of part with plastic shell on it so I can send it to a NOS vendors.

 

 

I will contact the Technical advisor for 1974 thru 1977 Riviera  from the Buick club to get his thoughts and possible contact person that may have the module.

 

Did you contact the Buick Farm to see if they had part?

 

Bob

[Philippe Racicot]

I have looked at the Buick Farm website years ago to search for that part and I didn't see it but I didn't contact them.

 

I'll try to take a picture of the plastic box that's still in the car. It's in storage right now. 

[Philippe Racicot]

I just took a picture of the black plastic box. I removed the relays that were taped around it.