1999 F355 Convertible top not working

I have a 1999 F355 Spider that I'm working on. Customer's issue is that the convertible top is not working. After reading about this topic, I see that it's a common issue. With engine running, doors closed, and parking brake set, I unlock the latch and windows go down slightly. I push the top back and I get one beep. When I press the switch to lower the top, it continually beeps and nothing. I have operated the top with the override buttons and it works fine. After reading about the common issue with the seat potentiometers, I checked them and found the passenger seat pot was not changing with seat position. I pulled it apart and found the potentiometer drive was broken. I repaired it, adjusted it to read the same as the driver's seat, and checked it. I operates the same as the driver's seat, but the top is still not working. What other requirements do I have to verify for top operation?

 

(EDIT: disregard my previous post).

There is an interlock under the seats composed of an orange white wire which runs in a loop between the seats and the ECU. Make sure the connectors under the seats are plugged in.

The wire can be seen in the wiring diagram (going to pin A11 of the controller):

https://www.dropbox.com/t/1YyWFlwSzZDJrTXw

 

After the windows have gone down automatically, do they still respond to manual input from the window switches? They shouldn't, until the roof has gone fully down.

If they do, check the microswitch at the bottom of the slider on the left hand primary piston. The switch should be closed circuit until the roof is fully down.

 

If I remember correctly, changing the seat potentiometer requires recalibration by an SD1 computer so that the computer knows where the seat limits are. It is now very hard to find an SD1. You should also check the limit switches in the top down positions.

 

Thank you for this diagram. This is exactly what I needed.

 

Thank you. I'm assuming an SD1 is a Ferrari specific tool?

 

The windows do not respond to the switches. Microswitch at the windshield is ok.

 

OK. Sounds like the top fully down switch is ok. Need to put my thinking cap back on again.

If you set up the seat potentiometers similar to each other, you may be able to rely on the existing settings in the Roof ECU, in which case, you might be able to forgo the use of the rare and extremely expensive Ferrari SD1 tool.

Note that the SD1 tool would probably tell you the exact problem anyway. Sometimes it's better with some problems to take the car straight to a Ferrari dealer.

 

When you pull back on the roof manually and let go, will the roof drive closed using the secondary cylinder system using the centre console roof switch? Note that the bypass switches do not drive the secondary cylinder system.

I'm just wondering if there are any interlocks in the secondary system preventing the primary system from working.

Here's a hydraulic summary:

https://www.dropbox.com/t/fT0QXxfWHKZp0qBS

 

Just remembered that the top fully down switch (Sx) is irrelevent to roof operation. It only feeds into the Window ECU.

Looking at the hydraulic diagram, the internal switches in the primary hydraulic actuators (S1 and S3) stop the pump motor running at the fully down position (plus 1 second time delay). I'm not sure if the first cylinder to reach fully down stops the motor or if both cylinder switches are required. i.e. I don't know if it is possible for one switch to break in the closed position to stop roof (down) operation. Anyway, in theory, the pump should run for at least one second even if the switch is broken.

To me, it doesn't sound like a power issue. You're getting bypass switch operation and also the seats are working, which means you're getting power to the toggle switches and to the roof ECU. If the seats are working with the roof switch, it means the roof switch itself is ok.

 

Thank you. I will check these

 

It's not a power issue, it's a logic issue. If it beeps at you and does nothing, it really means the computer is thinking that the seats are not at their most forward position, or it thinks the parking brake is not pulled, or the doors are not closed.

 

Yes and no. The roof buzzer beeps on my car if the "AC System/Instrument" fuse in the passenger footwell has been pulled (but, from memory, it does that just with the ignition on, not with the roof pulled back).

The "AC system/Instrument" fuse powers the roof and seat switches and some of the Roof ECU internals. Of course, there would be a lot more not happening if that fuse has blown.

 

This is what I did to my spider: I removed the seats, removed the potentiometers from the motors, wound the pots to its maximum forward positional values, then hang them out of the way so their values never change. The CPU always will see the seat pot values to be at most forward positions and will always work. I have to remember to manually move the seats forward as to not interfere with the moving roof. That is a small price to pay for a working roof.

I do understand if the perfectionists do not like that approach.

 

Thank you. That's what I figured. Another member sent me a schematic. I'll be be checking everything in the morning.

 

Slightly off-track, but here's an example of the roof buzzer going off with the AC System fuse pulled...

https://www.ferrarichat.com/forum/threads/no-gauges-and-beeping.600828/#post-146624246

 

Regarding the handbrake, there is only one microswitch on the handbrake which inputs into the roof logic and the handbrake warning light, so if your warning light is on with the handbrake applied, it's a good sign that the microswitch is ok.
I did notice some strangeness in the WSM diagrams though. The microswitch is supposed to play a role in the bypass switch logic, too, but on my Australian car, the bypass switches worked with or without the handbrake on.

Regarding the door open switch inputs, there is a disagreement between one manual and another regarding the Roof ECU connector pins. According to the Workshop Manual, pins B09 and B10 should have the signals from the door switches (driver and passenger respectively). However, looking at some paper wiring diagrams for USA cars, there are no wires attached to B09 and B10. I'm having trouble tracing the wiring from the doors in the paper wiring diagrams to the Roof ECU.

Workshop Manual-derived diagram:

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Just had a play with my roof after 6 or 7 months of inactivity...

When opening the roof with the roof switch, my seats won't move unless the doors are closed and the handbrake is on. If your seats are moving (with the roof switch), then I'd say that the door switches are ok. I didn't pull my car to pieces to check for wires on B09 or B10.
Despite the single beep when I initiated roof opening, the roof did start beeping at me after the seats had moved. I needed to give the roof a gentle push and the beeping stopped and the roof started to move.

I have seen "beep" microswitches (S9) with bent levers or loose mounting screws causing problems (see left rear side of canopy).

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Thank you for your input. Seats are not moving and car just beeping when I press the top switch after the first initial beep when I push the top back.

 

OK, check your basic inputs:

1) door switches (do your door lights and interior light work when you open the doors?)
2) check condition of switch in the top left rear corner.
3) handbrake (does your handbrake light come on on the instrument display?)
4) try yelcab's technique of bypassing the seat potentiometers.
5) confirm all the inputs are reaching the Roof ECU as per the diagram

Note that it is theoretically possible for there to be faulty contacts on the bypass switches (even though the bypass switches work). The automatic roof operation still relies on a circuit path through the bypass switches.

 

My notes say seat pot should read around 4.4k ohms when the seat is all the way forward, between the pink and yellow wires.

 

Has anyone had any luck with just bypassing the entire system and converting it to a manual only type drop top?

 

Some folks have had some luck....



Has something major failed? If you have a mechanical issue, converting to a manual top might not help.

 

I am still in the research phase. I haven't started taking it apart yet... Thank you so much for the video!