I just bought the car a week ago and drove it 2 1/2 hours to get home with the driver's seat in laid-back mode. My shoulder and neck were killing me by the time I made the trip. Only the driver's seat is power and it doesn't work. I have a 1985 Fleetwood Brougham parts car but everything under the seat looks different than the Coupe except the rails and the color coding on the wires in the plug is different. The previous owner had taken the transmission to the seat out and all I see is a large motor and the cables. I put the seat from the parts car in the coupe and it didn't work. I am getting power to the switch and to the plug under the seat. I'm not sure if the motors in the parts car seat even work. Does the seat have to be grounded via bolting it down snug to the floor? I'm debating on whether to fix the stock seats or get some sports car type seats (recaro, etc). If I don't keep the stock seats, I would like to get something with some lubar supprt in black leather that is non-power and reclines, maybe even some from a parts yard. Any suggestions or help will be appreciated.

 

How many motors are under original seat?

 

There is a large motor, not looking at it right now, but from memory I'd say about 5 inches long. There is also a molded plastic transmission? with three smaller motors in it. I'm not sure if they are the original seat rails and motors. One of the mounting feet looks as if it has had some cutting and welding done to it. Almost like someone retro fitted a track from another model of car. All of the stock plastic covers fit on it though. I found a set of non-power rails at the parts yard today from an 86? Buick Centry? wish I could have found another non-power set-up from a Coupe. that would have been a direct bolt in. The Centry rails bolted right up to the seat but will need some slight modification to get them bolted to the floor. The distance from front to rear of the mounting points is greater than the distance of the factory studs on the floor of my Coupe. I don't really care about the power seat that much. I've decided to go with some leather reclining sport seats, aftermarket seat belts, and a center console when I move some of my other toys and have some play cash. BTW Slowroll, I used to be dwpnz on here. My account went haywire. I knew my log in info by heart and it kept giving me the s.o.s., so, I started over. Hey, I finally got a Coupe to put one of my 500s in. I bought the Big Inch Cadillac Book too. Any suggestions on a worthy engine stand that won't break the bank? I figure I will build one of my 500s by the time this 4100 dies. It runs pretty good for now though. Anyway, It's good to be back. Thank you for the help you gave me in the past.

 

The old system you have tends to be more reliable and less expensive to fix. What do you hear and/or see when trying to move seat? There is a relay for motor. The motor attaches to transmission. Transmission contains soleniods which when energized cause cables to spin they attach to gearnuts or actuators to move seat. As far as the big block thing find 77-80 big block car for donor first so your have most of what you need. The swap will be straight forward. Areas which will require fab will be cruise control and a/c since ecm controls both.

 

The transmission has all of the mounting points broken off and was in a box in the trunk, so I hear nothing at all from it, obviously. I don't hear anything out of the large motor either. I do have power to the plug though. I have given up on the power seat. I went to the local u-pull-it yard took the buick Centry rails back(that didn't fit) and got a passenger side non-power seat rail from an Olds 88. Came home greased the inner rails , did the same to my existing passenger side rails, and wah-lah....no more power seat pains. It was a direct bolt in with no modification and all of the trim pieces were identical to my passenger side pieces. I don't really care about the power seat that much and I will never have to buy anything else for the seat now. I discovered that some GM cars came with spacers in the seat-to-rail mounting points and got a few of them and the longer bolts, just in case. If later I decide I would like to bring the front up and get a little recline position, I'll just throw in a spacer on each side. No more seat Gremlins.
On the 500 swap, I actually have a good running 1980 Fleetwood that is for sale for $1600. If it doesn't sell soon, I may use the drivetrain out of it and just save the 500s for later use. Thank you, Slowroll.