Help with electrical system

While jump starting the car (it sat idle for 2 month) my dad reversed polarity on the cables while attaching it to the rear point ( in the engine bay). Now the starter does not work, but everything else seems to be working. I checked all the fuses related to the engine and they all ok. Blown radio fuse was replaced. There is a set of relays above fuse box, and I wonder if one of them is blown. Any help would be greatly appreciated.

Relay for ignition? 2nd in from left on top row of relay carrier under carpet in back seat.

Where exactly is that? Before I start ripping the car apart..

Behind the rear seats under the carpet. The computer and a relay box is there. The computer is on the left (looking out the back window) and the relay box is on the right. I am only guessing that this could bethe cause.. Does your ignition switch work? All lights, dash, radio, etc? The only other thing I can think of is that you fried the solenoid on the starter. Do you get at least a "ckick" when you turn the ignition? Or nothing? The relays I would look at behind the seat would be (at least on the 99 C2) top row second from left (this is the ignition relay) and the botoom row extreme left (this is the starter cutoff relay).

My car is a cab and I see some relays behind the carpet, but they are behind rollover popup bars and very hard to get to. Most of the electrical stuff works. Ignition key turns everything on, except electrical top, which just clicks and does nothing. I will have to go visti a dealer and talk to a technician. I just hate to fltabed the car. if it's something as easy as replacing a relay or a master fuse....

The starter circuit for the 996 Porsche is pretty standard. Voltage from battery to the ignition switch to the permissive relay (permission from depressed clutch or (or Tiptronic Park/Neutral)) and to the starter solenoid. If you open the engine lid and use a flashlight you can see the starter with electrical connections on the solenoid. It is just below and left of the throttle body. When you turn the ignition switch, the permissive relay should power the smaller terminal (50) which should engage the solenoid and apply power to the starter via terminal (30). There is a fusible Element in the power distribution box, but if this were blown you shouldn't get power to the other items you say are working OK. You might check the voltage at the smaller terminal 50 on the solenoid when an assistant attempts to start the engine. (Be careful here) If you don't get any voltage then you might trace backwards to the permissive relay behind the rear left seatback. If you get 12 volts at terminal 50 but the starter does not turn, then remove the plastic cap on the supply cable to the starter to see if you have voltage there. It should have 12 volts always. It may be possible to free the starter by banging on it in case you welded up something or reverse rotation disturbed the brushes. The starter comes out toward the rear by removing the throttle body and the plastic intake distributer if you are inclined to do it yourself. It may be possible to jump the starter by putting 12 volts on terminal 50 in case you turning the ignition to start does not give any voltage there. Again be careful. Use insulated jumpers with clips and keep your hands out of the engine bay and any wires away from rotating parts. Once the battery is dead you lose the usual things: Radio Code (depends on model) DME adaptation - there is a procedure for readapting Stored Control Module faults Tiptronic adaptation Power Window limit switches - there is a procedure for this too Trip computer, Clock, Date - easy to set PCM data Fuel Level accuracy (depends on model)

Thanks guys, Do you have schematic of relays behind left rear seat? Thanks

According to my schematics, the start lock relay is in position 7 on the 12 socket relay panel. It is a standard 4 plug relay. Although I never checked this particular relay on my own car, typically the cube shows the relay schematic as a relief in the molded plastic. 87 From Ignition switch 86 coil 12v 85 coil ground 30 To starter Solenoid If you remove the relay and jump from 87 to 30, you bypass any start permissives or locks.

Also: There is a seprate 40 amp maxi fuse associated with the relay panel, described as position 13. It must be outside the 12 cube relay panel. Not sure how it is wired without more digging. If it powers the whole relay panel the rear spoiler (relays 3 & 9) would also be failed. Also, there is a box near the battery called the current distributer. It contains a number of fusible links visible if the cover is removed. There is an 80 amp link for the ignition lock. Does turning the key have any effect?

The fuse in the relay box is for the auxilary air pump and has nothing to do with the starter relay. The number 7 relay is the second row left as I stated above. He still hasn't answered whether or dot he gets ANY noise from the starter when he turns the ignition on. Is it a tip or manual?

There is no noise from starter at all. The lights do not dim on the dashboard. Another thing that is not working is convertible top. There is click sound in the back, but top does not operate. I can turn head lights and they dim when I turn ignition to start engine, so some relays must be working and it indicates that ignition switch is also operable. It's a TIP transmission. Thanks

Have you checked the relays mentioned above yet?

I pulled the carpet behind rear seats and seen the box with relay. in my cab they are behind the pop up bars housing, so they are extremely hard to access. How do I check a relay anyway? Do I go buy a new one from the dealer and try replacing it? Because I don't think they will have any visible marks from burning out. There is also set of dozen or so relays above fuse box. Can any of them be the ones?

http://www.autoshop101.com/forms/hweb2.pdf

By reversing the polarity with the jumpers, the obvious item you might have fried is the battery itself. It sounds like the high power items are the ones that are not working. The headlights lights dimming when ignition is turned to start may indicate the battery cannot keep the voltage up. You can measure voltage cell to cell (about 2 volts each cell x 6 cells = 12 volts). Put the voltmeter leads right into the liquid (acid). All cells should be the same 2V. The link shown by 1999Porsche911 shows your exact relay, and a previous post already mentioned how to jump this out of the circuit. A cheap voltmeter at radio shack is less than the cost to flatbed your car. We want to hear how you solved this problem.

The verdict is in... Fried ECU. Waiting to get a replacemant and looking for IPO to pay for the price tag of ECU -> $2.2K plus labor