Thru-Hull Type VTS Module Test Procedure
The following procedures test the Thru-Hull VTS Unit that incorporates the motor and is found on most all 1995-2004 models that had electric trim. Due to the metal clamps they put on the vts boot, a common problem is the boot failing and allowing water into the module. Before testing the wiring, pull the cover off the vts to insure there isn’t moisture/corrosion in the box. Also, before testing make sure the VTS 7.5A fuse (in MPEM or Coil Box) is ok. If you get a "click" but no up/down, that’s usually a blown 7.5A VTS fuse and you would need to know why it blew. I’ve found the procedures below handy in troubleshooting various VTS problems.
Also, if you find your VTS boot is leaking or even if it isn’t and you still have the old gear clamps, I sell a Boot Update Kit that will fix any future leakage problems.
Details can be found HERE.
VTS Module Test
This is a test for the wires going INTO the VTS module. Note the trim unit does not have to be removed from the boat for these tests. To perform the tests, you’ll need to disconnect all cables going to the VTS and follow the procedures below.
- VTS Power Wires:
Red/purple to black wire = infinite resistance in both directions. It should read at least 1 Meg ohm. This is a critical measurement. If it is between 1 Meg and 10K ohm, you may be able to use the VTS box but it has begun to fail and will be running down your battery. Less than 10K and you’re going to need a new module.
Purple/white to black wire = 10 k ohm in both directions when the trim is in the middle point or with the sliding shaft removed. It should read about 5K to 6K (K=1000) if the trim is in the full up or full down position. You should be able to see the change in resistance when the trim reaches full up or full down.
Purple/white to red = infinite resistance in both directions.
- Push Button (UP/DOWN) Wires:
Blue/white to black wire = 32 k ohm in both directions.
Green/white to black wire = 4 m ohm or infinite, depending on polarity.
Blue/white to green white = 4 m ohm or infinite, depending on polarity.
- Trim Gauge Wires:
Brown /white brown/black = 24.3 ohm (+/- 20%) with VTS down / 171.3 ohm with VTS up.
With VTS in middle position the resistance should be between 24.3 and 171.3 ohms (goes in steps of 14.7 ohms).
- Trim Motor Wires:
Green/orange to blue/orange = 0 ohms in both directions.
The motor should draw 1.7A when running and 3.8A peak.
Note that the specs above were found online so may have errors.
Always refer to the oem service manual if you’re not sure of a procedure.
Finally, if you find your module or motor is bad, let me know since I may have a new or used one available!