355 Convertible Top Control Module Repair

Is that something I can do while the seat is out or does it need to be plugged into the car?

 

You can do that with the seat out. Note that I edited my last message.

 

Great! What's the process? Never tried anything like this before...

 

I guess one possible way would be to get a reading from your passenger seat and compare them (seat fully forward).

Check outer pins first to see if the wiring is ok for that.

 

Unfortunately, I can't safely access the passenger seat wiring due to right space in the garage. But when I stuck my head underneath to have a look last week, the wiring looked correct.

 

This might be difficult, because I don't know what your wire colours are. Typically, the colours on the potentiometer itself are brown, yellow and pink. You'll have to match up your modified harness to these colours.

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If you have no access to the white plug on the passenger seat, then we will have to come up with a ballpark figure based on your driver's "outer" pin resistance reading.

 

Black, light yellow and yellow.
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Which position is the light yellow in? It's hard to tell from your photo.

 

Matching wire colours is going to be a headache on your car.

Comparing these photos...

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Your black (and I think brown/white) corresponds to the standard pink.

 

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So...
Standard pink ("top" in photos) = black = brown/white
Standard yellow (middle)= Dark Yellow = ???
Standard brown ("bottom" in photos") = Light yellow = ???

Can you get continuity readings/colour matches at the splices without cutting the splices?

 

Here's what I have written down as I'm completely cutting out that trailer harness.

And since I'm cutting the harness out, I will have full access to all the wires for testing.
View attachment 3800275

 

Thanks, that clarifies things.

For future reference, could you add the labels "B16" to the two grey/yellow wires in your drawing, "B19" to the Grey/blue wire, and "D5" to your two black. These labels are Roof ECU plug and pin numbers.

 

Maybe before cutting the wires, can you do a resistance check on the:

1) potentiometer light yellow and black wires (or any corresponding wire colours further downstream). This will give you the type of potentiometer (5k?)

2)potentiometer yellow and black wires. Should be near value "1)" with the seat fully forward.

3) potentiometer yellow and light yellow wires. Should be minimum with the seat fully forward.

In theory, 2) + 3) should equal 1), but due to the vagaries of resistance measurement, you might find theory doesn't match reality.

 

Check out #14 and let me know what you think...

https://www.ferrarichat.com/forum/threads/re-post-of-f355-spider-potentiometer-photos.131465/#post-136344918

 

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You can use these values, but there can be variations from car to car. Aeroengineman used "standard colours". My colours vary from his colours and your colours.

For reference:

 

This is something my Ferrari tech can calibrate easily when I bring it in for service if he has the correct tool, right?

 

If your tech has the old Ferrari SD1 tool and your pot hasn't been moved too much out of its factory position, he can fine-tune it, but you really need to take measurements before you put your seat back. If you get mid seat position resistance values with your seat fully forward, you will probably have issues with calibration/seat movement.

 

I'll pull out my meter tomorrow and take some readings. Will report my findings of course.

I'm searching for the right mounting clip for the TE connectors I bought so I can pin it properly to the seat frame like oem. Having a hard time since Amazon doesn't give a whole lot of info...

 

Meter set at 20k

Yellow and black: 4.93
Light yellow and black: 4.91
Yellow and light yellow: 0.01

 

In theory, the light yellow and black should be higher than yellow and black, but I doubt it will be an issue. A 20 kohm meter range isn’t the most accurate.

Re-splice and fit the new plug and you’re good to go, but, to be honest, no one will notice your trailer park plug and it has smooth edges, so it’s unlikely to snag on the carpet.

Your tech can fine tune the seat calibration.

 

I can change the setting on the meter and re-test. LMK what you suggest.

The trailer wiring was just garbage work IMO. And it left a black mark on the carpet from dragging. The best part about the TE connector is it accepts a mounting tab that should be able to snap in place where the oem plug was. I ordered two different kinds to make sure I get the correct one. I was also able to avoid any splicing. I went directly from the end of the wire on the seat to the crimp connector on the plug. Plenty of OEM slack.

 

I just installed the connector in the car and two of the three crimp connectors from the trailer harness just pulled out easily. That's what happens when you have a big crimp connector for a thick gauge wire splices to a thinner gauge wire. It just doesn't make a good crimp. I think the trailer harness was 12ga (guess). Now I have solid connectors that won't pull out.

Next task is to recondition the seat before I put it back in. Has some wear I need to address. Then I'm going to look for the leak in the top hydraulic system.

As always, I appreciate the help from all!

 

Waiting for the mounting clip
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