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8 Position Cadillac seat for 37 Chevy coupe -Stumped

8K views 38 replies 8 participants last post by  51fordnut 
#1 ·
Hi all,
I'm completely new here and hope that I am putting this in the right place. I have been looking for days now on the internet and on this site and I have yet to find the answer that I need to make this all work. I have seen similar posts on here but none were my issue, so here I go.
I have a powered 8 position driver’s seat with memory out of a 2001 Cadillac Catera that I’m trying to wire. This seat did not come with the computer control module, but I have no plans on using the memory buttons anyway, but I do however want to use the factory switches that are on the side of the seat. I thought I had this all figured out since I’m familiar enough with electronics to get myself into trouble! I have actually wired many cars from the ground up, but this has me stumped!
(see attached drawings) This is what I know - The factory setup on the side of the seat consists of 4 micro SPDT switches mounted to a circuit board. The circuit board has 6 wires (actually 7, 1 is for the memory portion and is not needed) for the sake of this discussion, I have 1 pink and 1 black wire that is common to all 4 switches. The other 4 wires are red, green, blue and yellow. 1 goes to each switch. (So, red with black make the motor go down, red with pink makes the motor go up. Green with black, green with pink, etc…) I bought 8 SPDT relays, because the micro switches will not carry the load of the motors, 1 relay for each position.
Now, here is where I get lost. If I hook up 1 motor (let’s say forward and back) which is the green wire, it works great. Green to pink goes forward, green to black goes back. When I hook up the rest, that black and pink wire are common and all 4 motors go at the same time regardless of what position I select.
What am I missing here? Should I have diodes in the line somewhere? The only thing I can think to do is either buy new switches and mount them in the side panel, or try and modify the circuit board so that I have 4 wires off of each switch coming out. This sounds like a lot of work. Seems like there has to be an easier solution.
 

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#2 ·
The only thing I can think to do is buy new switches and mount them in the side panel
That solution makes the most sense to me.

The last rod I built, I used the power tracks from 2 driver's seats from '92/'93 Ford Tempos. The track takes 2 wires, hot and ground, with the control panel mounted on the front of the seat. I welded the power tracks to the bottom of 2 bucket seats from an '86 VW GTI.
 
#4 ·
I suggest that you Google "2001 Cadillac Catera power seats" as I did, and you will find a 38 page PDF file which should give just about all the info you'll need to wire up your seats. (Sorry, I'm not clever enough to post a PDF link, or I would have......)

Additionally, it's been my experience that you'll need to wire-around, or defeat, the memory function, to get your seats to operate properly.
 
#6 ·
schematic

The attached schematic is the basis for controlling a DC motor (forward and reverse).
The switches are spdt-center-off-momentary.
The relays are common automotive spdt.
For an 8 position seat you will need 16 relays.
Check the I-net for good prices on relays. All Electronics | Electronic and Electro-Mechanical Parts and Supplies at Discount Prices
Check out the original seat motor controller which must have used relays but some experimenting would be needed to find out the coil voltage.

vicrod
 

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#7 ·
Thanks vicrod, all that you mentioned seems spot on. But why would I need 16 relays? I only have 4 motors. forward and back= 2 positions. so I should only need 8 relays. The problem that I have is the factory switch which has 2 wires common to all 4 switches. The scenario you show is exactly how I have it wired, and that works great when only one motor is hooked up. But when I add more motors, they all go at one because of the common wires in the switch.
 
#8 ·
Your looking at it wrong. #30 to the motor are commons. The 80's are not duplicate hots, they are the contacts, single pole 4 throw switches. Think 2 way light switches in a house to help get your head around it. 16 relays needed.

No I am not drinking, use the module you will be better off. Computer modules make life easy compared to working 16 relays.
 
#9 ·
oops

Sorry, each position requires 1 relay. Total 8 relays required.
All of the control switches should have a + common feed.
Each control switch will have a fwd. wire and a rev. wire to each respective relay coil.
The relays NC contact will control the + connection.
So in the fwd. condition the rev. relay maintains the + path while the fwd. relay (when energized) selects the ground path.
In the rev. condition the fwd. relay maintains the + path while the rev. relay (when energized) selects the ground path.


vicrod
 
#10 ·
My apologies for referring you to an incomplete document; I should have read it to the end. However, I do have one other suggestion that has worked well for others trying to wire up Cadillac seats; get the PASSENGER seat to work first. With no memory circuitry, once it's figured out using the confirmed required relays, you'll know what circuitry can be bypassed in the driver's seat wiring for operation.
 
#11 ·
We actually have the passenger seat up and running, but the difference with that one verses the drivers seat is that the motor load is running through the switches. Weird that they make the passenger switches large enough to carry the load. Because the divers seat normally has a computer module, it uses the micro switches which then has to have the load pushed to relays.
 
#12 ·
In checking, this might be your answer, posted on this site in 2004 by HDUFF:

"The passenger seat is a conventional power seat with conventional relays and wiring. Wire up +12V and a ground and you're good to go. But the driver's seat uses solid-state relays and is connected to the car's main computer. As a result, many people believe that the seat won't work uless it's installed in a Catera and hooked up to the car's main computer. They are wrong.

All you lose by not being connected to the Catera's main computer is the three memorized positions that the main computer can store. Still, many people could not get the seats to work. The secret is all in the wiring, but the solution is hidden in the Troubleshooting section of the Cadillac service manual.

First, there are three +12V connections: two thicker wires and a thin wire. The thicker red ones (#1 & #3 in the service manual) are connected to an always-powered source. The thinner red one (#4) is connected to an accessory-powered source. The brown wires (#2 and #5) are the grounds. The data control wire is #6 and is not used. The secret wire is #7, a thin grey wire. In the Catera, this is connected to the door switch that controls the courtesy lights. When this wire is not grounded (when the door is open), the seats will not move. I just grounded it permanently; it seems the GM engineers did not want you to move the seat with the doors open. It's also important to wire #4 to a circuit that is hot only when the engine is running or it will drain the battery. That's all there is to it."
 
#13 ·
crdnblu, you are doing a great job in trying to help me out and I really appreciate it. So, thank you. I also saw that post, and he is talking as if you still have the computer module unit, which I don't. I could buy one, but I have already eliminated all the plugs that would normally plug into it and have just the wires from the switch and the motors. If I buy new switches, I could have this up and running in a few minutes, but I want to use the factory switches. I may unsolder the switches from the circuit board and solder on my own wires which would work too, but then I would have to duplicate the circuit board to hold the switches in place. If I soldered on my own wires, then I would have 4 wires per switch (2 to each motor relay) and none common to each other. I was just hoping that I could add some diodes to prevent all motors from going at once.
 
#14 ·
Yep, I understand. Sounds like it's time for some alligator-clip jumpers, & diodes, to double-check your theory re/ the number of relays required. Additionally, here's an "off-the-wall" thought: Looking @ the pics of these seats, would it be possible to use a modified passenger seat switch assembly for the driver's seat? They look to be about $50 on eBay. By the time you wrangle out the relay(s)/diodes wiring, this could be an easier fix.
 
#15 ·
Good thought crdnblu! I didn't even think of getting switches from another passenger seat. I may do that. I was also thinking that if I did unsolder the switches from the circuit board, I could actually grind off the board mapping, then put the switches back in the original hole and solder on my wires. This would allow me to keep the switches in their original position and I could snap the board back into place. All good thoughts here!!
 
#16 ·
Please keep us informed as to your efforts, and results; your success could be a big help to others trying to use later model seats in their street rods. As you know, more, & more vehicles are using multiplexed wiring architecture for their accessories to simplify wiring, keeping costs & weight down. To adapt the newer hardware to our older rods will continue to tax our creativity.......
 
#17 ·
I'm not clear on your drawing...... Your drawing indicates each micro switch controls two movements or 8 actions. What are the other actions? How many motors are they controlling?

Grn & Pnk = FWD
Grn & Blk = BACK
Red & Blk = DOWN
Red & Pnk = UP
Yel & Pnk =
Yel & Blk =
Blu & Blk =
Blu & Pnk =
 
#20 ·
Here's what I came up with for the fwd/back seat motor. I assumed the Blk wire was the ground and was hooked to the normally closed terminal on the switch. You need to unhook the NC terminal on the switch, you only need the NO portion of the switch to energize the relays. The relays will reverse the polarity to the motor just like the original switch etc......
 

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#21 ·
One of the low trim level versions of he CTS came with Non memory drivers seat.The harness was wired with the heavier switches to hook to battery voltage. Switches were heavier to accommodate the current rating. Also the switches would interchange in the seat .
I would shop for a wreck with the non memory harness.
Maybe LKQ or a U pullit yard? Just sayin
 
#22 ·
Solved

EOD Guy, thanks for your help. I didn't see your post till this morning. I figured thing out yesterday. So, what I have is 4 motors (2 positions per motor) 8 positions. The problem that I had was the 2 wires that were common to all 4 switches because when I hooked them up to the relays the switches were not independent and would cause all motors to go at the same time regardless of what position I selected. If I was running 12v power through the switch lets say to the 4 colored wires (green, blue, red, and yellow) then when I activated the switch, it would send the power out the pink and activate the 4 up/forward relays. Vise versa for the down/back position. If I tried to run the switches as a ground circuit, the same thing happened. I just didn't have enough wires coming out of the switch panel.
Here is how I solved it. I took the switch panel apart (see attache photos) and found the pink and the black mapping on the circuit board, Then I used a small dremel tool to cut the mapped circuit and separate each switch. Then I left myself enough space next to the switches to clean a new spot off so I could solder on/connect a black and a pink wire to each switch. This would give me the 2 wires per switch that I needed to complete the circuits independently. After I soldered it all up, I added some liquid electrical tape to each contact, zip tied all the wires and put the switch control back together. In the end, I used the switches to complete the ground circuit for the relays.
 

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