Seadoo VTS Motor Controller Replacement Project

This project is intended as a DIY replacement to the original Seadoo VTS controller found on 90's Seadoo X4 (XP & SPX) hull PWC’s. These VTS units often fail due to a combination of burnt circuit board traces, corrosion, and failed reed limit switches. Failed units are known to cause electrical issues with the MPEM (ECU) aswell. This controller replaces the original one entirely but still uses the stock handlebar trim buttons, motor, and lead screw assembly. 

How this motor controller works is basically still similar to the original one with two double throw relays for directional motor control with the motor wired to the common terminals of the relays. However, instead of reed limit switches, normally closed hall effect PNP sensors are used for there improved reliability, availability and replaceability. Specifically, PNP NC switches ensure the system fails safe, as if one or both switches were to become disconnected from the circuit, it disables travel in that direction. The limit switches must be present to supply the MOSFET gates with +12v which enable the trim buttons to energize the relay coils. 

The limit switches are mounted in place of the original controller circuit board within the trim motor assembly housing. Careful scoring and prying with lots of isopropyl alcohol will get the original board and potting compound out, have patience. The limit switches are mounted on slots to allow for fine adjustment of the trim range. The sensors require facing a specific pole of the magnet embedded in the trim rod to work. It is recommended to replace this magnet with a new ¼” round neodymium magnet as the original magnet is most likely corroded away. Also included is a shaft collar for the worm screw. This ensures the motor can never unwind the worm screw all the way out of the trim rod. 

Electrically, everything is mounted to a piece of 3” by 4” perforated board with all external connections being either pin headers or quick connects for ease of replacement. Once assembled, it is recommended to spray the board with conformal coating. The enclosure box should be watertight, however additional water proofing is always a good idea in marine environments. 

The controller is wired to a through a 5 amp fuse to the battery, and has its own power on switch and relay. Nothing is wired directly to the MPEM, just remember switch off the unit when not in use! A 5 amp fuse seemed adequate for my motor, however others may find their motor to draw more current and should fuse it accordingly. The automotive SPDT relays and associated wiring are rated for far more than the motor should ever continuously draw in this application. I chose to use relay sockets so that relays can be replaced easily however this is not strictly necessary. Additionally, a TVS diode is wired across the motor terminals to protect against voltage spikes when changing the motors direction. Free wheel diodes also included across all relay coils in case the relay used does not have them built in. 

I estimate this projects cost around $55 in parts, which while more expensive than the common 451M relay fix, my controller still maintains limit switch functionality. 

Parts list, schematics and wiring diagrams and of course model files for the associated brackets and enclosures all included. Enjoy!