The 370Z roadster's top hydraulic system consists of one pump, and eight hydraulic cylinders connected to the pump via sixteen tiny hydraulic hoses. The exciting news is that all the hydraulic components can be repaired for very reasonable prices. All eight convertible top hydraulic cylinders, hydraulic hoses, and the hydraulic pump for your 370Z are sold by Nissan only as a complete set, part number 97093K or 970931-ET0A. No need to buy a complete hydraulic system, when you can have your components upgraded by Top Hydraulics for far less money! Nissan Dealers do not generally know this, because Nissan does not get the components supplied separately, and thus the dealers are only trained to replace complete hydraulic systems.
The easiest cases to diagnose are leaking hydraulic hoses or leaking hydraulic cylinders, because you will find the leaked hydraulic fluid somewhere, once you have partially opened the top.
This may all seem complicated at first, but we will break it down into bite-sized chunks with pictures (with the help of forum members), and (in time) we will come up with a fairly easy to use decision tree and DIY for diagnostic and repair. At least, that's the goal, as time permits on my end and as forum members/readers are willing to chip in with pics and descriptions of their repair progress. (My introductory post from yesterday is still "under moderator review", as oftentimes happens when a new member writes something lengthy with links in it. I don't blame the moderator at all for taking a day to read through it, especially when I created that post on a Saturday. Moderators' work is much appreciated!)
Top malfunctions can be electrical, mechanical, or hydraulic. I haven't heard of mechanical problems on 370Z tops yet, so those will not likely play any major role in the future. On the electrical side, there could be bad switches/sensors, or bad wires (wires going either to the position switches on the latches or wires going to the travel sensors on some of the cylinders), a bad pump motor, or a bad top controller. The top control module (ECU/computer/controller) is mounted next to the hydraulic pump, directly under the soft top storage compartment. I have not heard of a bad soft top controller on a 370Z yet. If there is a fuse blown, then that's typically for a good reason. We would need to look up if a 10A or 15A fuse is used only for the soft top controller, or if it is shared with some other consumer that actually caused it to blow. The hydraulic pump has a dedicated fuse, probably 40A. If the pump fuse is blown, then it is obvious that you need a pump rebuild.
The switches at the latches (rear bow latch that latches down the rear window section and front latch that locks the top to the windshield) are a reliable sort of micro switch that normally does not go bad on its own or from a lot of use. If one of those switches is not giving the proper signal, then that is most likely either because the latch did not get actuated far enough, because there is dirt around the switch (unlikely), or because the wire going to the switch is compromised.
There are travel sensors on some of the cylinders. Those travel sensors are clipped onto the cylinders' bodies. When there is one sensor only near where the shaft comes out of the cylinder housing, then that sensor detects the cylinder reaching the extended position. If there is only one sensor near the bottom end of the cylinder, then that sensor detects the cylinder reaching its retracted position. Sensors on both ends obviously can detect the cylinder's general position status. The sensors themselves rarely go bad. If there is an electrical problem, it almost always is a bad wire going to a sensor or a micro switch.
Bad wires can be found and fixed, and that's not rocket science! Again, with the help of forum members, we can create a good DIY for the most common failures and their fixes. Let's get some momentum going!
Next, I will post some basic instructions on manual unlocking the top, so that you all can do the basic checks of the system without going to the dealer, even if the top is stuck in the closed position.
Klaus
