F355 Spider Power Seat Issue

I am having trouble with the passenger power seat only working in one direction. I was finally able to get the passenger seat out and have narrowed down the problem. There seems to be a relay inside a black electronics box that is attached to the side of the hydrolic pump for the top. You can hear the click coming from the box when you move the driver's seat back and forth. The passenger seat only makes the click sound in one direction. I verified that the issue is not with the switch by using the passenger side switch to control the driver side seat, so it must be inside the box or wiring related. I can also move the passenger seat in both directions by switching polarity on the wires, so it is not motor related. Ferrari only sells the box as a very pricey complete unit. I'm thinking about opening the box and see if I can just repair the one relay that is causing the issue instead of replacing the entire box. Does anybody have any experience with this, or any other thoughts of what to try?
Also, when I measure the voltage on the passenger seat motor wires with a meter, I see 12V when the switch is in the forward direction and 0V when it is in the off, or reverse direction. I believe some relays inside the box select forward or reverse polarity.

 

Alright, I pulled the box apart and there are two Siemens relays (P/N V23081-C1061-A303). They are obsolete, but still available through resellers. I am requesting quotes now, but it looks like they are around $75.00 each. I will try to attach a picture.
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Just for anyone's information that may have the same issue, it appears that Tyco makes an equivalent part. Here is the link with the electrical specs: http://catalog.tycoelectronics.com/TE/bin/TE.Connect?C=1&M=BYPN&PID=164541&PN=V23081C1061A303

 

Actually, since I run a business in the semiconductor arena, I contacted Tyco and asked for samples. One or two ought to do, right?

 

Actually, only the passenger seat has issues. It only moved forward. So I should only need to replace that relay.
If Tyco decides not to send me samples, then I guess it's time for the Dremmel tool. I'll cut the top off and see if the relay can be repaired. If so, I'll repair it and Epoxy it back together. I know it's not the proper way to fix a Ferrari, but at least I didn't use duct tape.

 

Just heard back from Tyco. No samples. Minimum order is 252 units. :-(

 

Hi Mike,

I have come across this site and many like it. So far, they have all required minimum orders of at least 10 units. The best pricing I have found so far is 10 for $215 or 20 for $244.

- Tom

 

I am going to pull the board again soon. I have a business trip next week, so it will probably be after that. I intend on hooking it back up without the black plastic case and measuring the voltages to the relays to verify that the relays are receiving the signal to switch, but are failing to switch. This will prove beyond any doubt that the relays are the issue. If I find this to be the case, I will certainly try the "bigger hammer" approach first. If that doesn't work, then the soldering iron comes out, and maybe the Dremmel tool, and I will try to open the relay. If I am unsuccessful in repairing the relay, then I guess it's time to order 10 or 20 of them. Maybe if anyone else has the same issue in the future, I can sell some of them to get my money back.

 

I pulled the board and did some diagnostics with a meter. I found that the voltage is not being applied across the relay coil, so the relay is not the issue. I traced it back through a transistor and resistor to a Motorola PLCC (I think). I also traced the switch side through some logic to the PLCC. The next step would be to apply power and probe each node to see if any of the transistors are bad. Other than that, I guess I need to visit the junkyard to find a different board.

 

OK, I replaced the ECU and now both seats work in both directions. Now I need to understand the wiring connections for the potentiometers. The connector on the potentiometer below the seat was cut off, so I need to attach a new connector. I have the connector, but I need to know which wire on the potentiometer connects to which wire on the harness. Can someone help?

Thanks,

Tom

 

Here's some pictures for reference
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I now see why the potentiometer was considered a possible culprit to my passenger seat only moving one way. In my case the potentiometers were disconnected though. When I replaced the ECU, the problem went away. Then I connected the passenger seat potentiometer. Since I had no feedback on how to connect the wires, I just connected them randomly. Worst case I would get 4.7K Ohm without any variance capability. After connecting the potentiometer, the seat would again only move back. When I disconnected the potentiometer, the seat moved both directions again. I am assuming I connected the potentiometer in the worst case scenario, fixed 4.7K (my luck so far), so the ECU thinks the seat is all the way forward and will not let me move it in that direction. I will switch two of the wires and see if that resolves the issue.

 

See http://www.ferrarichat.com/forum/showthread.php?t=207662 for further information.