I have a query over the way the trunk opens on my XLR and wondered if anyone could confirm the way their XLR works.

When I open the trunk, the following sequence of events occur in this order:

1/ The turn signals flash
2/ The hydraulic motor for opening the mechanism starts and the front (wings) of the trunk lid start to lift
3/ The trunk unlatches
4/ The lid lifts to the full height.

It seems to me that 2/ and 3/ are the wrong way round. The timing delay between 2/ and 3/ is very short, but there is no mistaking that the lid is trying to lift before the latch has properly released. This seems an unusual design and is certainly wrenching the latch.

Given that there is a signal (circuit 5960 - rear compartment lid pulldown actuator signal) from the latch to the hydraulic pump motor control (top control), I am guessing that that should signal the motor to start after the latch has released. If that is so, I suspect that the latch in my XLR is defective. (This is not the same signal as is sent to the BCM, the 'latch released' to BCM signal is working just fine (circuit 744))

If anyone could confirm the sequence they see, I would appreciate it. (I use the fob, but it is much the same with the release in the trunk lid)

And as an aside, it would seem that we don't have a trunk on these cars, instead we have a luggage compartment or a rear compartment. Index under 'L' in the w/s manual. Also, the description in the manual of how it works makes no sense at all and is incompatible with the wiring diagram. Looks like Cadillac changed their minds. Does a later version of the w/s manual have the correct description? (It is on pages 8-67 and 8-28 of my '04 manual)

I just tried my 04. It does the same thing. You can hear the pump kick on about a quarter to a half second before you hear the latch. The wings go up a split second before the back to but I believe it would do that even without the latch because of the leverage in the hinge. I think yours is probably fine.

My 08 lifts from the rear end first. AS the pump SPOOLS UP the latch releases the deck and it lifts FIRST at the rear and then without binding to it's up stop position. When it returns to the latched position, it does so with the leading deck edges lower throughout the travel and the 'latch action' is the LAST motion I notice. The deck 'hits the seals' and THEN the deck latch 'pulls it down' to lock. I see premature failure in a "badly timed deck system", so 'I would think' sensor adjustment and re-programming seems to be the next step. I say this because YOU NOTICED the unusual/rough deck lid action, and brought your question here. Mine is very quiet, smooth, and it moves 'evenly' throughout it's travel. I suggest your's should too. GOOD LUCK

I just tried my 04. It does the same thing. You can hear the pump kick on about a quarter to a half second before you hear the latch. The wings go up a split second before the back to but I believe it would do that even without the latch because of the leverage in the hinge. I think yours is probably fine.

Thanks for the description. Yes, it sounds like I am describing 'normal'. It is not great engineering though, and I do wonder what that signal is for.

Does anyone have access to Cadillac to ask if this is a bug in the top module?

Regards

My 08 lifts from the rear end first. AS the pump SPOOLS UP the latch releases the deck and it lifts FIRST at the rear and then without binding to it's up stop position. When it returns to the latched position, it does so with the leading deck edges lower throughout the travel and the 'latch action' is the LAST motion I notice. The deck 'hits the seals' and THEN the deck latch 'pulls it down' to lock. I see premature failure in a "badly timed deck system", so 'I would think' sensor adjustment and re-programming seems to be the next step. I say this because YOU NOTICED the unusual/rough deck lid action, and brought your question here. Mine is very quiet, smooth, and it moves 'evenly' throughout it's travel. I suggest your's should too. GOOD LUCK

Thanks for the feedback.

Re opening, I don't think I would describe the process as lacking smoothness, but I have noticed the strange sequencing (actually I listened to it more than watched it), and thought that it was poor engineering. Given the existence of the signal from the latch to the top module, it does look like it could be a programming bug. The fact that the front of the deck lid opens first means that the latch bolt is not parallel to the latch mechanism when it releases, that is why I described it as 'wrenching' the latch.

Re closing, that is exactly how mine works, the latch swings round and clamps the lid down as the final step. If you are careful you can do this with the lid up, use a screwdriver or something to press on the latch, as you push it down it will suddenly swing into action and cam down. Don't let your fingers be near that! This how I tested circuit 744, the trunk lights go out at the same time. If you do this, you MUST release the latch before you attempt to close the lid proper. As the hydraulic motor does not run, the top module 'knows' that the lid is up. Much the same happens if you put the top down with the trunk lid up, that bit of the sequence is skipped.

On my 04, the unlatch thunk and the pump start are simultaneous, and the lid goes up evenly. There isn't the slightest hint of the "wings" starting to go up first. This is both with the fob button and the touchpad.

On my 04, the unlatch thunk and the pump start are simultaneous, and the lid goes up evenly. There isn't the slightest hint of the "wings" starting to go up first. This is both with the fob button and the touchpad.

--- Mine works identically. When was the last time you had your Folding Top Firmware updated? The last revision I'm aware was released in Feb '09.

CC :cheers

--- Mine works identically. When was the last time you had your Folding Top Firmware updated? The last revision I'm aware was released in Feb '09.

CC :cheers

To answer that, all firmware was updated to latest recently, in the last 3-4 months anyway.

If you hear the latch 'thunk' at the same time as the motor kicking in then you are describing much the same behavior as I am. It takes the latch about 0.5s to release and the wings will have started to lift before the latch has fully released as per the other replies in this thread. You can watch this delay in the latch by opening the trunk, manually closing the latch with a screwdriver or something (not your fingers!!!) and then pressing the fob release. It takes a moment (about 0.5s) after the latch motor starts for the latch to release. If it is the same as my Riv, the mechanism is a motor spinning a helix that winds the latch release mechanism along about a 1" travel. It takes about 0.5s for the motor to pull the traveller (release plunger) the length of the helix. The sound of the XLR and Riv releasing are very similar!

If you are saying that the wings do not lift immediately that the pump starts then perhaps a fluid level check is in order? On mine the instant that the pump starts, the wings are lifting.

I would want good engineering to have the latch finish its release cycle BEFORE the pump starts up, not running together.