Help! TDSZ2: lights remain always on even if switched off on VLCD5

[Mixsoft]

Hello,
I've been using a mid motor TDSZ2 since 2018 and it has worked well so far (I just replaced the battery after 4 years and the VLCD5 due to broken buttons).
Recently, the following problem appeared: the lights stay on even if they are off on the VLCD5 controller.
I removed the front and rear lights and measured the voltage on the light circuit: on the front and rear terminals the voltage is 4.9V when the lights are supposed to be off and 6.3V when I turn them on from the VLCD5 controller. The 4.9V is enough to produce a weak light on the tubes.
Also, when the lights are turned on from VLCD5, the battery drains quickly.
Could this problem be caused by the VLCD5 controller or is there a problem inside the TDSZ2 mid-engine itself?
Thanks for the help
Rob

 

[Sturmey]

Hi. Firstly, just to get the terminology right, The VLCD5 is usually called the 'display' unit. With the TSDZ2, the controller resides in the motor casing beside the motor. The controller is the thing that converts the battery Direct Current into the timed three phase type motor current.

Anyhow I had a similar problem with a front light that intermittently flashes on a front hub kit despite the motor turned off at the display unit. Its not something I worried about as I have a physical switch between the battery and the motor controller. I am inclined to think this problem is possibly related to dampness/condensation in the controller as its in the controller (afaik) that the actual switching takes place.(which in your case is housed in the motor unit)

If I had this problem, I would consider opening the motor unit cover and checking for condensation/dampness around the internal controller and letting everything dry out over a long time (bring bike indoors,using heat or whatever). I would also consider having some convenient means of disconnecting the battery (e.g switch) when bike not in use. I would not be inclined to replace the controller if I could help it as the bike is running ok.

PS Also check for dampness/water in light units, wiring etc