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1956 6-way seat motor field wire problem

Started by Hillbillycat, September 18, 2022, 02:48:47 AM

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Hillbillycat

Switch OK.
Relay OK, opened up and contact cleaned (justin case sinc it was openend up).
Harness OK.
Lockout solenoids OK.

Wire #55 (pink) get´s hot when motor is operated (down and forward). Using the jumper wire method I get current draw (dome/map light dims) as soon as this pink #55 wire get´s connected to the #1 feed wire at the switch connector.

Motor armature (green) to ground has continuity.
Both motor field wires (yellow and pink) also have continuity to ground. I also get a beep between both field wires.
Is this a normal reading? I doubt it since the pink #55 field must be faulty hence motor will spin in one way only.

Relay and solenoids click normal when jumping the switch like described in the shop manual.

The whole power seat had issues due to the switch when I got the car years ago. Repairing the switch did the trick. Lever assembly had been relubed by PO so no binding here.
However, sometimes, when accidently bumping the switch with your heel while driving or getting in out out of the car, the motor could turn on and keep spinning and spinning untill you wiggled the switch.
Does this indicate something? Is there some cutout switch inside the motor that went kaput shorting a field coil?

Seat and assembly still in car. I want to drive her this fall. I think if I take out the spindle and motor the bench will slide to and fro so no safe driving.

Michael Petti

Just a thought, but you said you are bumping the switch with your heel. If it's like mine the parts are plastic, and the force may have broken something. I would start there.

J. Gomez

Quote from: Hillbillycat on September 18, 2022, 02:48:47 AMSwitch OK.
Relay OK, opened up and contact cleaned (justin case sinc it was openend up).
Harness OK.
Lockout solenoids OK.

Wire #55 (pink) get´s hot when motor is operated (down and forward). Using the jumper wire method I get current draw (dome/map light dims) as soon as this pink #55 wire get´s connected to the #1 feed wire at the switch connector.

Motor armature (green) to ground has continuity.
Both motor field wires (yellow and pink) also have continuity to ground. I also get a beep between both field wires.
Is this a normal reading? I doubt it since the pink #55 field must be faulty hence motor will spin in one way only.

Relay and solenoids click normal when jumping the switch like described in the shop manual.

The whole power seat had issues due to the switch when I got the car years ago. Repairing the switch did the trick. Lever assembly had been relubed by PO so no binding here.
However, sometimes, when accidently bumping the switch with your heel while driving or getting in out out of the car, the motor could turn on and keep spinning and spinning untill you wiggled the switch.
Does this indicate something? Is there some cutout switch inside the motor that went kaput shorting a field coil?

Seat and assembly still in car. I want to drive her this fall. I think if I take out the spindle and motor the bench will slide to and fro so no safe driving.

L. Stark,

Because these motors are the "shunt type" due to the torque load they required to carry both the field and armature would require a separate voltage source.

The "Green" wire "armature" would get the +12V from the relay (Red main source wire) once the relay is activated (on either forward or back operation), the second source to either "Pink" (forward) or "Yellow" (back) to the "field(s)" would be from the switch again this would be +12V.

If your "Pink" wire from the switch gets "hot" that is because all the power load is feed by just that wire, so the relay may not engaged to extend the +12V from the "Red main feed" over to the motor "Green".

Question, since only the "Pink" get hot, how about the "Yellow" does it also get hot?

From memory the "ground" to the relay would be from the opposite motor "field" wire, so placing the +12V on the "Pink" wire from the switch to the relay the ground for it will be on the "Yellow" side from the motor and vice-versa.

Good luck..!   
J. Gomez
CLC #23082

Hillbillycat

Switch is definitely ok. Problem is also present with switch disconnected and replaced by jumper wires.

The yellow wire does not get hot.

Should I jumper the red to the green momentarily with the swtich jumpered for i.e. forward motion? Then the motor should get the 12V from pink field over to the armature.

J. Gomez

L. Stark,

If you jumper the switch connector to 1, 4 and 3 per the Service Manual to move forward:

Do you hear the relay clicking?

Can you check the "Green" wire from the relay over to the motor and see if +12V is present with this setup?
#1 is the main power "Red" and #4 is the "Pink" going to the relay. If the relay does "not" operate with this setup you only get the +12V to the motor fields (Pink wire) and not over to the armature (Green).

The wiring diagram from the Service Manual is not clear as to how these wires go, I'm attaching on that will make it a bit clear on how these are setup.

Hope this helps.

Good luck..!
J. Gomez
CLC #23082

Hillbillycat

Thanks for the schematic. That is indeed a better diagram then in the shop manual.

Anyway, I checked like you suggested:

Relay does not click with jumper wires in 1,3 and 4. Clicks fine with yellow connected.
I was not able to hook up this setup and then crawl back to the other side of the bench to dive under to take the reading if the green wire has 12V. If I did the pink wire or switch connector would have melted down. The connector shows signs of melting at the pink pinhole already from my jumper wire testing. Grrrr.

I also wasn´t able to jumper one field and armature to 12V+ to check the motor itself. This is too darn deep under there. And I´m working upside down through the slot betwen bench and floor.
I simply want to avoid taking the bench out by all means.

BUT the seat did move normally one time to all directions when I started testing today with everything cold. Then it acted up again.


Lexi

I have a box of parts for both 2 way and 6 ways 1956 Cadillac seats, if there is something that you can't live without. Clay/Lexi

J. Gomez

Quote from: Hillbillycat on September 19, 2022, 03:32:49 PMI also wasn´t able to jumper one field and armature to 12V+ to check the motor itself. This is too darn deep under there. And I´m working upside down through the slot betwen bench and floor.
I simply want to avoid taking the bench out by all means.


Are you saying that you are not Mr. Fantastic from the "Fantastic 4"?  ;D

Quote from: Hillbillycat on September 19, 2022, 03:32:49 PMRelay does not click with jumper wires in 1,3 and 4. Clicks fine with yellow connected.
I was not able to hook up this setup and then crawl back to the other side of the bench to dive under to take the reading if the green wire has 12V. If I did the pink wire or switch connector would have melted down. The connector shows signs of melting at the pink pinhole already from my jumper wire testing. Grrrr.

Hmm all I can think off-hand is either one of the field windings is open or you have a bad ground.   ???

As you can see from the one I've posted the relay will get the ground to operate from the opposite side of the field coil, so is just a hunch on my side.

There is also one note I've forgot since this unit is bolted to the seat frame and not at the side rails there is a "ground strap" on the left side which bolts to the top seat frame and the mounting bolts to the main rails, not sure if you have it in place. This will be the only solid ground for all the pieces motor and solenoids.

Good luck..!
J. Gomez
CLC #23082

JungleCadd

Quote from: Lexi on September 19, 2022, 04:03:55 PMI have a box of parts for both 2 way and 6 ways 1956 Cadillac seats, if there is something that you can't live without. Clay/Lexi
any chance you have spare solenoids?
56 Eldo Seville

Chopper1942

The best way to check the circuits is to do a voltage drop test on each circuit. Start by connecting a DMM with B+ lead on the battery positive post and B- lead to the battery negative post.  Activate the switch. This is the battery potential.  Now move the DMM B- lead to the B+ feed wire to the switch.  Activate the switch.  the voltage should be with a few tenths of a volt (0.01-0.03) of your battery potential.  Connect DMM B- lead to the yellow wire or connetor at motor. Activate the switch and read the voltage. 

If you start with 12.V at switch feed and it reads 11.0V when activated, there is high resistance in the circuit. Check the green and pink circuits the same way. the standard voltage drop for a switch is no more than a 0.3V drop across the switch.  Since there are 2 switches in the circuit the voltage should be greater than 11.4V. If the circuit does not pass the test, move the B- lead to the yellow connector from the switch. Activate the switch. Should only drop very close to 0.3V. If much greater than 0.03V, needs switch. If OK, connect B+ lead to switch yellow and B- lead to yellow at relay. Activate the switch. Should only drop 0.1V.  If much greater, there is resistance in the yellow wire circuit. If OK, connect B+ lead to yellow at relay and B- to yellow for connector at motor. Activate the switch.  Should be close to 0.3V. Again if much greater, relay contacts are bad and you need a new relay. If OK, B+ to yellow of motor connector and B- to known good ground.  The motor should drop all the voltage. If not, check the motor's ground path.

By lookiing at J.Gomez's wiring diagram, the motor is grounded to the seat frame, the frame to the chassis. Connect B+ lead to motor case and B- lead to the battery.  Should be less than 0.3V (which should allow for all the connections from the motor to the battery).  If not, you have a ground issue. This should affect all the motor circuits.   If motor ground tests test OK, the problem with the yellow wire circuit is internal to the motor. Check the pink and green circuits.

The voltage drop across the solenoids is tested the same way.  0.3V across the switch, 0.1V on wire from switch to solenoid, and the solenoid should drop all the voltage 12.0V - (0.3V +0.1V) = 11.6V.

Remember you always have to have current flow in the circuit to measure voltage drop.  You can chec continuaty and resistance and they will read OK because current is not flowing in the circuit.

Below are some Youtube links that may help you understand voltage drop testing if you are not already familiar with this method of testin electrical circuits.  It's the only way to definately find an issue in a circuit.  Hope this helps. Good luck!

https://www.youtube.com/watch?v=9aioZN33xsA
https://www.youtube.com/watch?v=xerAp9Yd53Y
https://www.youtube.com/watch?v=DfLyh43iihM