Power seat switch question, 1965 Lincoln

[George W]

I’m having an issue with my power seat and I think it may be in the switch. Both the front and rear tilt functions work perfectly. The center “joystick” switch seems to activate the horizontal motion solenoid properly but it doesn’t activate the motor to move the seat forward and back. It used to activate the motor if the switch was pushed hard in the forward or rearward direction. Does the center switch have two separate sets of contacts, one for the solenoid and one for the motor ? Is there a schematic somewhere for the contacts or the actual wiring schematic of the seat circuits ?

[TonyC]

Your shop manual should have a schematic in the back of it, if '65 manuals were organized the same way as '66 manuals. How does the center switch behave when flipped up or down? The seat should raise and lower that way. If it does, or even if it doesn't, it could be corroded contacts in the switch...or, if the fault is limited to the fore and aft movement, engaging the motor and solenoid but no movement, it could be a seizure in the "transmission." I am guessing the latter, based on my own experience with Frankenstein's seat when it wouldn't move. Now, if there is no audible response from the motor, then the switch could be at fault; if that's the case, a new one can be had and installed...or replace the whole switch assembly which can also be done, though I see that as a bit wasteful. The center switch can be removed, maybe even disassembled.

But I think we still have to locate the root of the problem. Place your hand on the joint between the motor and transmission, then operate the center switch in all four directions with your other hand. If you feel it spin, or grab and jam, in all four positions, the switch is probably okay, meaning a more-involved surgery to the transmission is in order. If you feel nothing at all in any position, the switch may be the culprit.

---Tony

[George W]

I’ll try those tests tomorrow. I “think” by the way things sound under there, it appears that the solenoid is activating but the motor is not. The motor and solenoids work perfectly for both the front and rear tilt switches. There’s a wiring illustration in the TSM and Lincoln Land has a wiring schematic/diagram but I can’t tell from the center switch illustration how that center switch activates both the horizontal solenoid AND the motor. It may have something to do with that relay under there. The TSM does not define the actual function of that relay. Thanks for pointing me in the right direction.

[frasern]

A bit of a p.i.t.a, but another idea may be to disconnect the cables at the worm drive, to see if it works with the load removed. If one was dragging, or gummed up inside, it will stop them both.
I started freshening up all those drives from my parts car, to use in my '67 about a year ago, then stalled, but the grease inside is very dry, so repacking them should help them to run smoother. If yours were running slow before, that could cause the switch to overheat.

[TonyC]

Yes, a very good point, something I had to deal with myself in the past. And yes, it is a PITA to remove the cable lines from the transmission, especially if the seat is in place. But, it is bound to be a necessity, because that grease in the transmission will have turned into the consistency of peanut butter, causing it to do exactly opposite what it was originally supposed to do. Not only can that old stuff jam up the cables and overheat the electrics; it can also cause such an overload on the gears inside the transmission that they will strip out. Then, when that happens, you'll hear a very loud spinning-grind noise with no movement. Hopefully it hasn't gotten that far in your case. New gears can be had, but not easily; usually you'll have to hit up the Usual Suspects and hope one of them has gears to sell. Preventive maintenance is the better route. It is best to invest in a tube or two of PTFE grease, remove the transmission, disassemble and clean it out, and repack it with the new grease.

It can be a little easier to access the transmission if you unbolt the seat from its track and lean it back into the rear, out of the way of the mechanism. There are four bolts and nuts that hold the seat on the mechanism, one at each corner.

---Tony

[George W]

I did the up/down test with the center switch and that works perfectly. The forward / back function will work occasionally if the joystick is pushed hard in the fore or aft positions. I’ve pulled the switch assembly out and I’ll see if I can get some contact cleaner down inside and see how that goes. I’ll follow up afterward by checking / cleaning the seat gear box if I can. It was quite a pain just to get the switch out and disconnected. The carpet is very much in the way and it appears that there are some fasteners that secure the carpet that are inhibiting the ability to easily move it out of the way.

[George W]

I did the up/down test with the center switch and that works perfectly. The forward / back function will work occasionally if the joystick is pushed hard in the fore or aft positions. I’ve pulled the switch assembly out and I’ll see if I can get some contact cleaner down inside and see how that goes. I’ll follow up afterward by checking / cleaning the seat gear box if I can. It was quite a pain just to get the switch out and disconnected. The carpet is very much in the way and it appears that there are some fasteners that secure the carpet that are inhibiting the ability to easily move it out of the way.

[RMAENV]

I would be betting on the switch contacts are burnt from moving the seat with the car off over the 50+ years of service. Running the electric seat with the car off caused a low voltage situation and over time burnt the contacts in the seat switch. It happened to me. Took everything apart, no issues, then a friend said we should take the switch apart. The contacts were black. They are supposed to be brass. A little filing, a few minor adjustments put the switch back together reinstalled and presto, back and forward began working again and tilts worked also.

[frasern]

This sounds more like a switch, the gearbox doesn't care how hard you push.

[George W]

Rob, how did you get the switch apart and back together again ? Were you able to un-crimp and re-crimp the housing ?

[TonyC]

Yes, it does sound like a wonky switch; it's actually logical, being that horizontal movement was/is invariably used more often than vertical adjustments. Hopefully it won't come down to replacing the center switch. But if it does, I have seen some sellers on E-Bay selling replacements. As I don't need one myself, I haven't followed any of them, just seen them...but some are among our Usual Suspects.

After you resolve that, I still recommend a surgery to the transmission before it ends up stripping a gear.

---Tony

[RMAENV]

As Tony said before it is easiest to work on if you unbolt the 4 bolts holding the seat down. Unscrew the switch from the seat and unplug it and pull it through. The switch comes apart easily from the back with the exception of the stem (handle) in the front. It has to be pulled STRAIGHT out to get the switch apart. If you pull on an angle you will break it.

It is pretty much the same idea as rebuilding the window switches. Cleaning up the brass contacts and re-arching the brass for better contact.

[George W]

Rather then take a chance on damaging the switch I’m sending the switch to John Brewer for refurbishment. I’m having some difficulty getting access to the seat bolts as the carpet is in the way. I may have to wait for the switch to be returned so I can move the seat mechanism to be able to gain access. There’s a button with an attached string through the carpet that secures the front and rear sections of the carpet together under the seat. It appears that I’ll need to cut that string in order to move the front carpet out of the way to access the seat bolts and the motor/drive mechanism.

[TonyC]

Hang on, you did mention that the vertical/tilt controls still work.
Before you disable the seat, try setting it to its highest adjustment with the tilt switches. That should help a little with access to the seat's anchor bolts (that is, the bolts that anchor the seat to the adjustment mechanism, not the mechanism to the floor). That way, while John is refurbishing your switch, you still can keep yourself busy by refurbishing the transmission.

---Tony

[George W]

Good suggestion.