355 Spider Top not opening: another one for the problem solvers

apply 12v directly to the pump to ascertain if it works.

 

The relays and motor are ok. You tested them with the bypass switch.

Here's a bit of light reading while I get my thinking cap on....

https://www.ferrarichat.com/forum/threads/spider-roof-window-logic.577843/

 

Is it possible to tell if the seats are stopping before they hit the forward endstops? I'm just wondering if the (position feedback) potentiometers should stop the seats before they hit the physical stops during the roof opening procedure. If the seats are not seen as fully forward, then the roof might not work.

I can't think of anything else which would stop the pump motor running (other than both switches in the main pistons falsely indicating top fully down).

New, improved wiring diagram for roof

 

I meant to say "sufficiently" forward.

 

Good point. Sounds plausible (unfortunately). I guess you could pull off the S5 electrical plug and, depending on whether the microswitch was normally open or closed, try again or jumper it and try again.

Unfortunately, not a simple/clean fix. There are people who repair these pistons, but it will be a hassle.

Anyway, let us know how you go with S5.

Cheers

 

Hmmm.... Having second thoughts about that switch... I can't see how it would transfer control to the primary pistons. It is only a single contact switch and this changes state at near (roof) closed. If the upper half is moving at all, then the switch is in the right position for (secondary) hydraulic operation in either direction. I don't think the primary actuators are dependent on that switch.

 

Possible correction: Looking at the hydraulic diagram in the manual, the "F1" valve symbol is a "2/3 way normally closed valve". You can find information online regarding the operation of this type valve. I don't see how the secondary pistons are hydraulically powered at all during the top opening process. Basically, when opening the roof, you manually pull back on the upper part of the top. Movement is allowed because the fluid in the secondary pistons is allowed to drain back into the reservoir (no hydraulic lock). The solenoid "F1" is only activated during the closing operation, allowing hydraulic pressure to close the top.

I stand to be corrected

Your original message sounds more logical. Are you sure you're hearing the pump operating to open the top part of the top?

If the motor is not running during normal roof operation and the problem is not the seat potentiometers, I guess you'd have to look at the roof ECU or perhaps the primary pistons' fully down switches.

(EDIT: Just noticed an error in my wiring diagram... or rather an error in the original workshop diagram which I didn't pick up... STANDBY)

 

Here's the hydraulic diagram from the manual for reference... I'll update it the more I learn about it.

Roof hydraulics

I've coloured the F1 solenoid valve in green to show which part of the valve is active when the roof (top half) moves to close. When the solenoid is powered, fluid is allowed to flow from ports 1 to 2 (I assume the arrow indicates some kind of check/one-way valve).

I'm not sure what the valves in the magenta rectangle do.

 

Same here. I've had to make a few corrections to my (hydraulics) diagram ... now up to version 5. Refresh your browser to view amendments to both diagrams.

If your motor does actually run for about 1 second when you attempt to open the roof normally, I have theory on how you can check the electrical switches in the main pistons: If you pull both electrical plugs off the main pistons this will simulate both electrical switches being open. i.e. indicating that the pistons are somewhere between fully retracted and fully extended. This may allow you to open the top (if the switches were indeed faulty and preventing opening).

 

Was there a reason why you said "windows already down"? Although the prerequisites for roof retraction are a long defined list, the individual steps of roof retraction are ruled by subsets of this list. e.g. you don't need the handbrake on to make the windows go down 2 inches. The handbrake switch doesn't "talk" to the window computer.

Can you confirm that with the windows up, that by cracking the roof open, that the windows go down 2 inches and no further? The final stage of roof retraction may need S10 and S11 in the doors to be triggered (whereas, say, seat movement may not need this). Pure speculation at this point, however. I just want to eliminate all the variables.

 

If you drive the roof (buttress) down half way with the bypass switch, will it drive back up again with the normal switch?

If it does, I suspect the main piston "down" internal limit switches switches. If it doesn't, it may be the seat pots out of calibration or roof ECU. Although, I think even if both "down" limit switches were permanently showing closed, the pump should at least run for 1 second.

 

Confusing....

Could you drive the passenger seat back with the normal seat switch? If so, I assume that the roof controller is happy that the roof is in the right position for the restoration of normal (manual) seat function.

I really don't understand why the roof controller would let the roof buttress go up but not down (based on seat position). The logic must be very specific, looking at certain switches in a strict sequence.

When you told me the roof went up normally, I thought that would point to faulty internal (fully extend) switches in the main pistons, but after you mentioned the passenger seat, the focus has gone back to the seat pots.

If the passenger seat does drive back with the seat switch, I guess the pots are only active during roof operation.

Anyway, we're shrinking the list of possible causes (I guess that's a good thing).

 

Power for the seat switches comes from the AC System fuse in the passenger footwell. If one seat works, the other should (unless the switch is faulty).
Power for the seats themselves comes directly from the Roof Controller. The Roof Controller fuses must be ok if the other seat works.

I doubt the seat switch has suddenly broken, but you could try swapping the plugs on the seat switches to see if the problem swaps over to the other seat.

If it's not the switch, I guess the seats still use the potentiometers in normal mode and that that seat is now out of calibration (?). Unless the potentiometer is back where it was before, it might need the Ferrari SD1 tool to recalibrate it.

 

Re-gluing the potentiometer claws is always a temporary fix. Have you seen this modification on the Jaguar forum?

https://www.jaguarforums.com/forum/xj-xj8-xjr-x308-27/repair-memory-seat-potentiometers-131192/

A bit of precision drilling required however.

 

I have removed both of my potentiometers from the motors and hanged them out of the way. The seats have to be manually moved out of the way when I activate the top, but that is a small price to pay for a very finicky top function. I cannot remember what values I left the potentiometers at when they are removed. Max or min value, I am not sure. This way, I never have to repair the pots, and I never need an SD1.

 

There are somewhat limited options available to us:

Repair it as shown in the link above (precision drilling required)

Have plastic injection molds made up for replacement claws (I'm not sure 3D printing has the required accuracy?). Not really economically viable.

There might be very old stock new Jaguar XK8 (X308) seat potentiometers still available, but at scalper's prices (U$300) and either the parts robbed from them or, if possible, Ferrari wires spliced directly onto the Jaguar potentiometer wires. Jaguar part numbers JLM21117, JLM21120, etc (I'm not sure if the gear ratios are identical). My searches for Jaguar parts usually come to dead ends.

Regluing the claw pieces (possibly with some precision pinning to assist the glue):
https://www.ferrarichat.com/forum/threads/fear-not-the-seat-pot-potentiometer-how-to-rebuild-one-without-removing-it.288373/
https://www.ferrarichat.com/forum/threads/a-quick-cheap-and-permanent-fix-for-broken-355-seat-potentiometers.280190/
https://www.ferrarichat.com/forum/threads/re-post-of-f355-spider-potentiometer-photos.131465/