Power seats are probally one of the most desired options on the TR. If only because the buckets offer such a crappy range of adjustment with the manual tracks.With the power seat option you get a six way range of adjustabilty. GM used two different designs of power seat motors on our cars. 1986 and older cars used a one motor type with a plastic bodied transmission to control the jack screws. They also used a 7 pin switch. The 87 and newer cars used a 3 motor type. No transmission was used as each motor controled a different function. They also used a 8 pin switch. The 3 motor type is the set up to have and those are the parts that I will be using to upgrade the older plastic type with. The reason for this upgrade is because those older parts are impossible to find and what little parts are still available are expensive.
www.gbodyparts has a limited supply of the OEM parts that are still available if you need them. What I hate about the older design is that the plastic housing becomes brittle over the years causing it to break into pieces and its a PITA trying to remove the seat from the car for repair when you cant gain access to all of the hardware. Those of us down here in the humid southeast know what the ozone does to plastic in a short time.Plus there is a plastic coupler that joins the motor to the transmission that will break at the most inconvienent time.All you need for the conversion is a set of motors from any 87 and newer full size GM car. The boneyards are full of Cadillacs that used them. Any 87-92 Deville or big Estate station wagon is what you are looking for. You can not use the motors from a 87-88 G-body. Here is why. Look at the pics I have posted. You will notice that the motors are set up in a specific pattern. Two motors on one half and one motor opposing them. On The G-body the side with the two motors faces towards the front
All the other models have the two motors facing the rear of the car. This orientation does make a big difference. Now if you look at your 86 and older seat track and on the right side where the cables join the jack screws you'll notice the distance between the front vertical jack screw and the horizontal jack screw in the middle of the track. That distance is different on the G-body tracks between the two types. It's just our luck that the 86 track shares the same dimension as the full size seat motor assembly. Now you see why you cant use the 87 G-body parts. When looking for parts just find a seat track that has the two motors pointed to the rear of the car. It's that easy. The motors are mounted to a steel plate which in turn is held onto the seat track with one nut. What we are replacing is everything but the seat tracks with the newer type of parts. Motors,cables everything. Make sure the motor assembly is tight against the jack screws on the side that has the short cable which should be the left side of the power seat assembly. If they aren't than that side of the seat isn't going to move. Okay now for the wiring. Most of the cars you will see in the boneyard will have the switch mounted in the door. Thats not good. There are a few models that have the switch mounted to the seat so keep looking. Otherwise you're going to have to make your own harness using the parts from the door mounted switch donor car. Hint: in case you haven't figured it out to save time try to find a full size car with the correct parts to cut down on the hassle. The 1985 RWD
LeSabre is a good choice for the correct parts.The 87-89 Bonneville is another. They were the cheapest,fully optioned out cars that I can think of. What you have to do if you are piecing parts together is splice the seat wire harness with the switch half of the harness connector. I didn't do this as I found the correct wiring in the boneyard so the factory shop manual would come in handy for this part. For some reason I dont think those two sections are color coded so you may have to experiment if you dont have the FSM.
Pic Directory
#1 86 and older motor and transmission
#2 86 and older plastic coupling
#3 <86 motor compared to >87 motor
#4 86 and older track jack screws
#5 86 seat adjuster with 87 motors installed
#6 87 seat motor and cable assemblies compared
Attached Thumbnails
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Eric Fisher OEM Parts Specialist
www.gbodyparts.com
252-332-8787
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86 GN 11.80@115
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1986
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09-18-2007, 07:30 PM
