Top pull down mechanism

[Budtee]

I have owned my 89 TC for 1-1/2 years. The top pull down mechanism was working OK when I got it in the Fall and in the Spring when I took the hard top off.  Since then I have not been able to get it to work.  (It is a 10,000 mile vehicle which has always been stored inside and has no rust or evidence of water leakage.)

 

I replaced the plastic housing and gear that was cracked and the paddle switch as well.

 

Now, when I press the "up" button the latch cycles up and down continuously until I release the button. The "down button"  does nothing.  (I checked the switch and even tried hooking it to the tonneau cover switch which is identical.)

 

Today I removed the entire mechanism.  With it plugged in and the top mechanism laying in the bottom of the recess where the top goes, the up button makes the mechanism go up and, when released, it stops. The down button then functions. When I tried to put the mechanism back in (with the plug in) I noticed a spark when the mechanism touched the stud where it mounts.  I then took a jumper wire from a ground and when I touched the mechanism I saw a spark,  The only things I have not replaced are the motor, which seems OK or the relay near the paddle switch.  

 

Any help would be appreciated.  

[Digger914]

You should have 2 relays, the square plastic canned one near the paddle switch and with only 10,000 miles on the car, I will assume the rectangular metal canned one is still on the lower corner drivers side of the mechanism.

 

The way this thing is supposed to work is that the position of the toggle switch on the paddle switch determines which position will be active when you push the switch up or down, the motor starts, the paddle switch moves from it's present position and feeds power to the directional drive relay and the holding relay. At end of travel the toggle switch on the paddle switch assembly is flipped and power to the latching relay is removed. When the up or down button is pushed it momentarily supplies power to the directional drive relay until the latching relay is energized, when the latching relay is energized it holds it's own contacts active and supplies power to the directional relay until the end of travel toggle switch is flipped.

 

If you only have one square plastic canned relay, it will be the latching relay, give it a couple of good raps, it could be stuck. Or you could have a bad wire connect, look at the wire connectors and wiggle the harness. Or your new paddle switch is bad. Do you still have the old paddle switch to test this with?

 

[Garnet & Gold]

Budtee,  Where did you get the paddle switch from?

[Budtee]

Garnet and Gold: I got the paddle switch from Amazon. I still have the box with the part number on it. AC Delco 16629927.  

 

Digger:  I will take it apart again today or tomorrow. I am almost sure that there is only one plastic canned relay.  I will take pictures.  Will also check the connections.wiggle the harness and rap the plastic canned relay.

[Garnet & Gold]

Budtee,  My notes indicate that this part number is for GM cars such as Cadillac, Buick, Olds, etc and the number for our TC is 16603820.  Problem I cannot find that part number anywhere.  Digger you might be able to assist here but the GM paddle is a trunk pull down only where the TC travels up and down.  A rapid way to tell the difference is the color of the plastic in the middle of the paddle switch, one is gray and the other is light brown.  The number is stamped on the part.

[Budtee]

I tried rapping and wiggling and checking connections.  No change.   

 

I definitely only have the plastic canned relay.  The wiring looks like it was modified. I took some tape off and found what looks like a factory splice of two wires to one.  Do all TC's have a second relay?

I was under the impression that the GM trunk pull down was the same. I will probably try the old paddle switch to see if that helps. 

 

Attached are pictures of the mechanism.
 

[Digger914]

Hey G&G, The GM paddle switch and this trunk pull down is on over a dozen different GM models and it is the rear top pull down for Cadillac Allante and the Buick Reatta convetribles. The original paddle switch for the Allante was replaced by the 16629927 but it was not a direct fit and requires a minor modification.

 

Hey Budtee, Now that I see what you have, the sparking and running makes perfect sense. Cadillac made a bit of a change after the first year to deal with the continuous cycling of the motor that would run batteries dead with the top on and with TC's built in 89 I didn't know we had any single relay setups, but as you only have one relay it's obvious that some of do.

Continuous cycling is caused by the improper placement of the lever on the reversing switch and you are going to need to do some engineering to get this ironed out. On the down stroke toggle and paddle need to agree that they are both in the same place at the same time. I remember that a couple of years ago both styles of paddle switches were available and I suggested you get the one that looks exactly like the one you have. My guess is that if this one matched the one you replaced, then it was probably replaced before you got the car and as it worked when you first got the car it has to be fairly close to right. Also my guess that the switch adjustment being off is why you had to replace the housing and gear.

 

If this was an 88 or newer Allante I could tell you how to adjust this, but we don't have the same assembly, just the same motor and our mechanical setup is better, it also wasn't made to be adjusted to the switch. Best I can tell you is run the thing half way down, flip the bottom toggle down, hold the paddle down and up should go up and down shouldn't go down. Flip the toggle switch up and let go of the paddle and it should only go down. After that getting the thing into synch with the mechanics is up to your own ingenuity, you may need to bend metal to flip the bottom toggle sooner or later, you may need to drill out the lever rivets and slot the mount to raise it up or down, or both. First make sure that the electrics work.

Edited June 12, 2016 by Digger914 (see edit history)

[Budtee]

I took it apart, again, and removed the motor and the paddle switch to look at the actuation tabs for the switch and the plastic arm that actuates the paddle. Since I wasn't sure how to proceed, I put it back together using the old paddle switch, AND IT WORKED FINE.  The plastic arm that actuates the paddle switch is held on with a rivet and it was turned slightly. Don't know if that was the problem.  

[Digger914]

If something is built absolutely perfect, it's as much by accident as it is intent. Everything is built to tolerance and a couple thousandths plus here, subtract a couple there, add a  couple more here, twist the arm a hair so it touches sooner than it should and it adds up. That, or your new switch was bad from the box.