Good day folks; just another XK8 with a top that won't work correctly. I've done quite a bit of troubleshooting though and read other posts so I'm hoping this is novel enough to warrant your time.
I'll begin by mentioning: I swapped all of the hydraulic lines with a Top Hydraulics kit ~6 years ago so there's no green shower for me!

Initial symptoms:
Initially, the roof was up (closed) but the rear windows were locked in the down position. At the time of the fault I wanted to lower the roof - but the rear windows simply went down and then the roof stopped responding to all requests. I drove home with the rear windows down but the roof remained closed.
Pressing Roof Close would not raise the rear windows despite the roof being closed and latched; it would engage the pump for a period of time, but it would then stop instead of opening the front latch.
I followed the steps in the video at the bottom to bypass the relays and manually raise the rear windows, one at a time. I then attempted to lower the top by pressing Roof Open - again, the pump operated for a short period of time and then stopped. When pressing Roof Open, the rear windows remain raised. At this time - as far as the Roof operation button is concerned - the rear windows are entirely inoperable.

I manually opened the roof with the battery disconnected - all windows down and front latch hidden. I then reconnected the battery and pressed Roof Close.
The pump engaged and the roof began to raise, but notably the front ram/hood latch remained in the closed position - i.e. the roof hook would arrive at the front latch and be unable to close.
I manually operated the front latch to allow the roof hook to engage and it immediately closed again.
Once the roof was successfully latched again - the rear windows did not close. In order to close the rear windows again I had to resort to the relay bypass.

Theory
I believe there are two possibilities as to what's going on here:
#1: A limit or position switch is failing to engage and as such the roof is operating in an incorrect "state" or thinks it's in an invalid position.
#2: A solenoid inside the hydraulic pump is failing to reverse the flow of the front hydraulic ram - as a result it's never correctly raising the front latch, and putting the system into an invalid position.

The roof pump will raise and lower the roof regardless of the position of the rear windows - which is dangerous - and the rear windows are entirely inoperable without bypassing the relays.
The front latch is only ever operating in the "close" method - it never operates in the "open" method - regardless of whether you press Roof Open or Roof Close.

Thoughts? Suggestions?

Below is the video - I didn't want it to embed but it seems that is just going to happen anyways:

 

Are there any messages in the INSTPK display? (ie. ROOF NOT LATCHED)

 

No messages- no hints there, unfortunately.

 

Did a little more investigation this morning - observations:
1). The front latch is receiving pump pressure to close for the entire operation of the roof - whether pressing Roof Open or Roof Close, so there's obviously something up with the solenoid's operation - but I can't tell if it's a logic issue or a pump issue.
2). The issue appeared after I was troubleshooting an alternator whine issue; during which I was rooting around in the wiring harness that runs by the fuel tank. Possible something got disturbed/disconnected/unseated there?

It'll be winter stowage time in the next few weeks so I may wind up manually lowering the window, removing the rear seats & trim and checking all the connections...

 

It is normal for the latch circuit to stay pressurized in the "raise latch" direction throughout the interval where the top is being raised.

When lowering the top, the latch will initially be pressurized in the "raise latch" direction but then that circuit's solenoid is flipped, isolating the latch circuit from the pump as the pump direction is reversed to lower the top. I can't remember what the pressure in the latch circuit looks like as the top is being lowered, but it wouldn't surprise me that it stays pressurized as you described.

 

Hmm... well it looks like I'll have to do some reading and see if I can figure out where the problem is. Based on what you're saying there that really confirms a logic issue (switch in wrong position/disconnected) rather than a solenoid failure. I'll go do some reading - there are a lot of threads on this forum where folks have had the rear windows inoperable (just like me) but all of the solutions seem to be related to just getting the windows back up, rather than addressing the core problem. I'd love to post a solution here if I can, as this is obviously a problem that affects a lot of owners.

 

Well, would you look at that!
Jagrepair.com proves to be an invaluable resource, yet again!

Got a few of these to go through





Time to go run through some tests, will post a reply when I've had a chance to go through this stuff.
The car's been on a trickle charger for the past few days so the first piece is already checked off...

 

My top just started acting up. Top will not lower, pushing button has no effect on top or rear windows. Battery is new, but none of my fuses are marked,no diagram on covers or list in owners manual?

 

I lucked out, just a loose connector on the button

 

I've been trying to reach Gus at Jagrepair.com to order the Pressure Valve Kit for my 2005 XKR convertible top. Emailed multiple times with no response. He doesn't list a phone number. Does anyone know how to reach Gus?