I had the usual symptom of a light on the dash and alarm when trying to drive.
One great resource I found on trying to solve this problem is on YouTube. TopHydraulics has made 10 videos explaining every component in the system and how to access them for maintenance. With this information and a shop manual you can, with patience and a pure mind, figure out what is wrong. If the problem is with the hydraulics, TopHydraulics can sell you a better and cheaper component than the dealer.
In my case, following the procedure of TopHydraulics Chapter 9, I was measuring 0.8 volts or 3.0 volts on all of the sensors (all voltages are based on roof position) and they were all correct, with one exception. That exception was the 5th bow striker sensor that was measuring only 0.1 volt. Note: there is a metal bracket that holds the control unit and I had to pull the unit out of that bracket to make the measurements. The unit just slides into the bracket without fasteners and with the right motion you can pull it out with all the wires attached for easier access.
Elsewhere in this discussion there is a photo of the wire harness that runs back to the storage lid where the sensor is located. It is on the driver's side and it is in contact with the 5th bow by (bad?) design. This is where my problem was and based on my reading it is a common problem. Within the wiring harness the wire had either fatigued or been abraded by the mechanism. Strangely enough I had measured a voltage reading but the wire broke completely as I was unwrapping it.
I really had to unwrap a lot of the harness to get to the problem, so I recommend perseverance on examination of the harness. Klaus asked me if I had actually unwrapped enough of the harness and it is a good thing he did.
I have included a photo of my re-wrapped harness for reference. I spliced in a wire and used heat shrink wrap followed by electrical tape. For the wire I used to do the splicing I tried to find a wire with the same copper and flexibility to avoid stress concentration where the two wires meet; if one wire is stiffer then the softer wire will eventually fatigue. I did solder the connection, so maybe I created a stress problem for myself. If this fails again I may try a connector.
The next time this happens I will just check the harness - this is relatively easy. Only if I see nothing will I get into the sensor voltage measurements.
