Convertible Deck Lid will not drop

[EmanuelJ]

Hello, first Thunderbird, first post. I hope someone will help a newbie out. My Deck lid is stuck in the up position. I've tried bleeding the system and using a jumper cable on the deck lid down relay. The top will raise and lower, and the deck lid flap will go up and down. When I activate the switch to lower the top, the top lowers, the deck lid flap raises, and the Deck Lid starts to drop; after it drops about 5 inches, it stops. I noticed the locks were not turning when the deck lid started to move. At this point, I can get the Deck Lid back up by pressing on the other side of the Top control switch. Does anyone have an idea of what's going on? I'm far from being a mechanic but a quick learner; plus, I want to avoid driving an hour to a repair shop in LA. Thanks in advance

[jtschug]

The vast majority of these issues when something will not move, it is an electrical issue. Air in the hydraulics or a weak pump manifest in different ways.

When you say you "jumped" the deck down relay, which relay did you jump and which pins did you connect to which other pins?

There are 8 relays which control the top operation behind the back seats. 4 behind the passenger side and 4 more behind the driver side.

Do you have a multimeter or a test light to indicate when wires are energized?

[EmanuelJ]

Yes, I have a multimeter. My top symptoms have changed. Somehow, I got the drop to come down on its own with the weight of the deck lid. The next time I used the Top Control Switch, the deck lid went up and stopped. I don't think the flap went up. I tried jumping the deck close relay behind the driver-side back seat. I have the Shop Manual, and it shows the relay as the one closest to the back of the car and on the inside. In the following example, it would be the dot in the top left position ( :: ). I have never been sure which 2 of the three connections to attach the jumper wire to in the relay boot. I've also been connecting the jumper wire to the circuit breaker for power; I hope that's what I'm supposed to do. Jumping the Deck Lid Close Relay did not drop the Deck Lid. So, once again, to close the deck lid, I disconnected the Hydraulic Cylinders from the deck lid and then jumped the Deck lock Relay to lock the Deck lid down. Thanks for trying to help.

[jtschug]

So a relay has three basic kinds of pins: Power feed, trigger, and power output.

The jumping process as described in the shop manual applies power to the 'power output' lugs directly. Remember there are two kinds of relays in this system: Relays with only one power output for the flip lid and the deck locks and relays with two power outputs for the top and the deck lid. If you are jumping the way described in the manual, you need a "Y" shaped jumper wire so you can put power to both power output lugs. One lug for the hydraulic motor and the other for the solenoid valve.

I prefer to use a different jumping process that is a little more involved. I make short wires that go from the power output pins to the power output lugs (use heavy gauge wire), then I apply power to the trigger pin. If jumping the relay this way does *not* work, then I use the other method. If the second method works after the first does not, then you know the problem is with the relay itself. If jumping the trigger works, then you know the problem is in the control circuit, not the relays or the power circuit.

I included the picture from the service manual that shows the first jumper method so you know which lugs are the power output lugs, the remaining pin is what I call the "trigger"

[jtschug]

The circuit breaker is probably OK for a power feed, but check with the multimeter to be sure it has power.

The manual instruction says to get power from the relay bus bar, this is the little bridge that goes between the relays. Check that with the multimeter, you should find it has 12V all the time, even when the car is off.

[Lee Craner]

If you want to know how the convertible top works, check out my earlier post, "64-66 Convertible Top Full Color Wiring Diagram". A 'search" of the forum should bring it up.

Lee

[Peterperfect]

I think you are confusing the fault disconnecting & changing things. Put this back as they should be & was then start again. Then take a look & check around. Most issues are bad or loose connections at the relays or plugs & sockets & the 15a breakers.
The clip should be connected to the bus bar. This is to cheat the relay & operate the pump & solenoid eliminating switches etc.
The reasons its stoped is probably one of the 15a breakers on the panel above the relays. These can go faulty over time.
If you hold the button to lower the deck lid & put the meter to ground & either side of the breaker you may see no volts on one side or the volts disappear after the 5 inch drop. Can't remember which one but it supplies the jack screws.
Its been a few years since I've repaired all of these cars, even owmimg 2 of them. Very complicated system but providing everthing is in order very reliable. I haven't had to change any switches after repairing quite a few. Hope this helps.
Peter
64 Convertible factory 'Roadster' options
62 Roadster