power seats

[spolij]

66 Deville convertible. I have six way power seats. all the functions work but after 10 seconds or so of operating nothing works. At the same time the convertible top doesn't work. 15 to 20 seconds later everything works. The motor and the wiring are not hot at all. I had taken the switch apart and there are a kind of small points in there. they look like they're in decent condition. I don't know if they would overheat or not.

I separated the motor and transmission and ran the motor it ran fine. I took the transmission apart and everything looked good. I put everything back together and it's the same situation.

I'm thinking there must be something that connects the top and the seat that is overheating. I can't tell from the electrical schematics.

Any thoughts?

[Big Fins]

It's a relay that is heating up and opening. Where it is on your car, I don't know. Others will though and chime in.

Cheap enough and readily available.

[Ralph Messina CLC 4937]

If memory serves me the seat relay is on the frame that holds the motor and trans. I don't believe there's a relay for the top motor. That's one of the culprit causes for the top switch burning out. I do have seat relay if you need it.

[bctexas]

I happen to have a '66 shop manual - it says that on '66 convertibles, and cars with power windows or seats, the 25 amp horn fuse is replaced with a 40 amp circuit breaker.  It is snapped into the fuse panel just like a fuse would be.  It looks like a small metal box.  It powers both the seats and the power top.  My '65 CDV has one too since I have power seats.

It sounds like the circuit breaker is being overloaded, kicks out and when it cools kicks back in.  At least, that would explain the behavior you are seeing.  There is a chance that the circuit breaker is defective.  The first thing I would try is replacing that.  If that doesn't help, there is an overload somewhere.  You will want to research what devices feed from that breaker, and disconnect one at a time and see which one is causing the issue.

Good luck!

[Ralph Messina CLC 4937]

I think bctexas has a better starting point for trouble shooting

[Big Fins]

Hard to discern from his post, but it appears as though he was operating the seats. Isn't the 66 power seat switch on the drivers door panel. If so, water may have gotten into it and corroded the switch contacts. He also states taking a switch apart, but not saying which one.

That small fuse panel breaker was used up into '72 for the power seats, windows and top.

[Ralph Messina CLC 4937]

John,
The seat switch is on the seat in '66.

[Big Fins]

Thanks, Ralph. Never had one, but I do remember the seat switch being on one of those years on the door panel. 

[spolij]

BCTexas I know the breaker your talking about I didn't realize it was for the seats. It sounds like the problem. that's what a breaker does, overload, blow and then reset.
I have a shop manual also but I can't find anything about seats, not even in the index.

I've got about four relays under the hood. What does a relay do? is there a way to test them.

Ralph if I don't have a relay is it worth putting in? I imagine I'd have to separate the circuits.

Big fins i was operating seat, the switch is on seat and I took apart the seat switch.
okay got a starting point so I'll start there.
thanks I'll be back

[The Tassie Devil(le)]

BCTexas I know the breaker your talking about I didn't realize it was for the seats. It sounds like the problem. that's what a breaker does, overload, blow and then reset.
I have a shop manual also but I can't find anything about seats, not even in the index.

I've got about four relays under the hood. What does a relay do? .........

A relay allows the full voltage to be supplied directly to the intended part, without all the power going through the switch.
The switch only requires a small amount of power to energise the relay, thus the direct main power source can be placed in a shorter distance from the battery, thus decreasing the chance of voltage drop.

That is why relays are used in modern cars, so the internal wiring can be light, and therefore the switches can be made lighter as well.

Bruce.

[spolij]

Bruce so the power for the part goes to the relay, some power goes to the switch. When you operate the switch it sends a signal to the relay to allow the power to go to the part.
Correct?
okay I put a circuit tester on the breaker and operated the switch, in a few seconds the light on the tester got real dim and the seat didn't work. a minute later the seat worked and the tester light was bright again.
so it seems like the breaker is the problem. So now I need to disconnect the seat and operate the top to see if the breaker blows. If it doesn't then I disconnect the top, hook up the seat and then see if the breaker blows.
Could the bad relay but a good breaker cause the breaker to blow?

[35-709]

You could replace the breaker in the fuse panel (not under the hood) to see if that solves the problem, but as bctexas pointed out, it could well be an overload somewhere.  The seat motor might need rebuilding, if the seat transmission grease is not old and hardened.

[The Tassie Devil(le)]

Bruce so the power for the part goes to the relay, some power goes to the switch. When you operate the switch it sends a signal to the relay to allow the power to go to the part.
Correct? 

Well, in a way, yes.   But, the two circuits are totally separate

Another way to describe the action of the Relay is to think of the Solenoid of the Starter Motor.

A really heavy cable goes from the Positive terminal of the Battery, and ends up on a terminal of the Solenoid at the Starter Motor.

Within the Solenoid is a coil surrounding a steel plunger, and a thin wire from that goes to the Starter Switch, and with the Starter Switch supplying a light current down that wire to excite the coil, (S terminal) which is grounded, creating an electric magnet, pulling the steel plunger sideways to operate the heavy internal switch inside the end of the Solenoid, causing the contacts to immediately energise the Starter Motor to turn the engine, via the bendix and ring gear.

BUT, before the plunger end creates the main switching contact, the Lever that is attached to the end of it pulls the Bendix gear into alignment with the ring gear.   Without this gear engagement prior to rotation, the spinning gear would destroy the ring gear teeth.

Bruce.

[bctexas]

I have a shop manual also but I can't find anything about seats, not even in the index.

Hi John, sounds like you are on the right track.  I found mention of the devices connected through the breaker on the page that lists fuses and their values.  Also, the wiring diagram for the convertible shows which devices are wired through the breaker.

FWIW, the 6 way seat in my recently acquired '65 does not work, though it does draw current.  I disconnected the leads that energize the transmission, and just powered the motor and it runs.  I suspect that, like the electric windows, the 55 year old grease in the cables, transmission and jacks is solidified.  I just need to get the seat out for a mechanical clean and grease job.  That did wonders for the windows.

Good luck!
Bernie

[spolij]

I sent you a message earlier but I'll fill you in now the second breaker in my fuse panel is a 25 amp 12/25 amp so I guess it's overworking and is finally given out. I'll get a 40 amp and put it in and I'll look for that page for the fuses. Most of the schematics in my book are blurry. I blew them up on the computer and pieced together larger units but but parts of it still aren't clear enough to read.
I also disconnected the transmission took it apart cleaned it out and put in new grease. I took it apart again the other day and it seemed to be fine grease is good, seemed to be working fine. The motor sounded like it had plenty of power until it quit.
Thanks for the help. I'll do an update.

[spolij]

Bruce you made that real simple to understand just for me didn't you, what a guy! LOL
I do think I understand it. Thanks

[spolij]

It worked. Put a 40 amp fuse in. Now the seat and the top work fine.
Thank you all.

[Big Fins]

Fuse or breaker? If a fuse, be careful.

[spolij]

My mistake 40 amp breaker.

[Bentley]

You'll have to forgive my ignorance, but what is the difference between a fuse and a circuit breaker? Also, what does a circuit breaker for these cars look like? Thanks.