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

OK, first a little background: car is a 1999 Spider and I consider myself to be at least intermediate-level with diagnosing and fixing this top when needed. I have encountered and fixed two blown hydraulic lines (K & L) in the past and I have rebuilt one seat potentiometer satisfactorily back in 2012. I've also fixed a microswitch (Sx) once, lubricated all frame joints a couple of times and replaced my elastic straps once. It has been functioning perfectly for 5+ years.

Yesterday while attempting to put the top down I went through the usual sequence: start car, e-brake on, doors shut, windows already down, unlatch the top from the windshield rail/pillar, push the front crossbar back while pushing the middle crossbar up, top beeps as normal. When I hold the top switch both seats move up normally. Then, when the top usually begins to retract, nothing happened. I can hear a relay click one time in the pump vicinity when the switch is initially pressed, but the pump motor is clearly not running and the top frame does not move. Letting off the switch and pressing it again will result in one more audible click. I can repeat this process as many times as I want. One press, one click.

Additional hints: the hydraulic fluid is full, both fuses in the pump area are good and the emergency switch works perfectly to open and close the top. So at least the pump motor is functional and this is not a hydraulic problem.

Any ideas? Could this be a relay problem with one of the two gray relays on top of the pump motor assembly?

 

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.

 

Thanks for the responses guys. The seats do move sufficiently forward (per normal). One tidbit I failed to mention is that after the seats move, the secondary pistons DO retract the overhead portion of the top. This is the point where there is normally a pause and then the primary pistons complete the retraction process.

My theory is the microswitch S5 is not releasing properly and is not sending the OK signal to the ECU to open the primary pistons.

 

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.

 

Qavion,

I am not smart enough to understand this schematic completely, but I am adding it to my aresenal. Will troubleshoot this weekend as I am out of town now. Tremendous work.

If I am reading this correctly you may be right....the secondary pistons may only assist with moving the roof closed-not open.

 

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.

 

Hi Ian,

You're detail oriented and I like that. The reason I mentioned the windows were already down was that I wanted to clarify the auto-window-down feature was note needed as I usually have my windows down. However today I have tested the process with both windows UP and can confirm they both automatically lower as they should upon releasing the front rail from the windshield header.

From here on I will refer to the first portion of the opening sequence (that is, the part above the seats and over the heads of the occupants) as the roof and the second part of the opening sequence (the part behind the seats when the roof is in the closed position) as the buttresses.

Moving down the slow, murky path of Spider top diagnostics, I can add a couple of small discoveries/updates to the list: In top-closed (up) mode, microswitch S5 is pressed in. Upon manually retracting the roof, the frame pivots on S5's roller and S5's button is released, signaling the initial beep that the roof is in the proper position to use the console switch. My initial hope was that S5 was sticking. In the pic below it is hard to tell, but the button is fully released. Anyone can check this by opening the roof with the engine off; you can hear S5 click--which signals the beep.

Also I can confirm your theory in post 9 was correct: the secondary pistons do NOT move the roof at all when opening--only when closing.

So to recap, my current status is that everything works normally until the roof is manually moved rearward, S5 is released and I get the beep. At this point the console switch simply produces a relay-type click in the pump area and nothing happens. The motor does not even try to engage.

Stumped for now...

 

Here is the pic of S5 after the roof has been moved back and the system beeps. View attachment Microswitch S5 - overhead roof section open.jpg

 

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.

 

Yes! The normal switch will move the buttress up but the interesting thing is only the driver seat moved back to its original position; the passenger seat stayed all the way forward.

Isn't this odd? When I rebuilt the driver seat pot 6 years ago the symptom was that seat would not move with the spider console switch at all. However today both seats will move forward, but only one moves back.

 

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).

 

Yes, both seats can be operated with the normal switches without issue.

 

Reviving this one. I removed the passenger seat today to have a look at the potentiometer. The white claw portion was cracked so I glued it back. Upon reinstalling, the seat will not move the the REGULAR seat switch. Both seats were fully operational before today's work.

I reversed the small gear wheel in the pot all the way in both directions several times and plugged everything back up. Driver seat moves fine, passenger seat does not budge.

So, there seem to have been man people over the years question if there are seat fuses anywhere. I cannot locate any. Does anyone know if there are [hidden] seat fuses anywhere? I am struggling to determine how I made this issue worse. I was surgical in removing and reinstalling everything.

 

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.

 

Thanks Ian. I was hoping you would respond.

Going to resume troubleshooting tomorrow. Thanks!

 

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/