Crawler gone wild weird ESC problem

Hello SGCers,

My SCX10 facing weird problem after some water dipping. Vehicle seems lurch and move randomly on its own. Only throttle affected steering seems ok.
Once brought back home weirdly it blasted forward full throttle (even with the switch set to 'off').
Had to discon the batts to stop it.

After disconnecting all lighting connectors and directly connecting the esc, motor and receiver to simplicity, i discovered this.

Even with the ESC switch set to off (and also on), there is a 7.4 volt output from the ESC constantly irregardless of on/off switch and without any transmitter inputs.

I am suspecting it is the ESC that screws up but since it is the HPI SC-15 WP (supposed to be waterproof) I am having doubts if that's the problem. I am running this with the Novak's Fifty-Five Crawler Brushed Motor.

I think the receiver is ok since all my LED lights responds accordingly to the transmitter inputs.

Anyone faced such problems or can advise/confirm if the ESC is the problem (before I purchase a replacement). Any further inputs on how to further confirm appreciated!   

Thanks and sorry for the long-winded write-up. My second rig to be downed in 2 weeks, and getting desperate.. lol   

Bro, points to note, even if it says WP on electronics, it doesn't mean its submersible. Its so call "splashproof".
Also unplug batt from truck if not using. Even if its off, It'll go flat the next day.

Bro oceanic, got it, thanks.. hmm seems not worth spending the extra $$ on 'WP' stuff.. Might just go for other ESC replacements huh? So far my 'ballooning' efforts on other rigs haven't fail me yet.. lol..   

Weird indeed.

Dirt may have collected inside the ESC, brought in through the water, causing flow of electricity where it shouldn't (e.g. turning on the output FETs even when the ESC is off).

Try taking the case of the ESC off and clean the circuit board, using an old toothbrush and Isopropyl alcohol.

If you don't mind a trip to Woodlands I'd be happy to take a look.

Ok laneboys Snr,

Will try to see if I can open this thing up, and not destroy any factory waterprofing.. lol
If I cant figure it out will get in touch with you again.

The factory waterproofing is usually a coat of conformal coating (https://en.wikipedia.org/wiki/Conformal_coating) on the circuit board. Unless you poke around with a sharp object it won't get hurt.

I haven't opened the HPI SC-15 WP yet (but we do have one in our Dingo too), but I guess the heatsink can be pulled off, and then there will be some latches on the sides of the case. Maybe some stickers have to be peeled back to expose the latches.

i have a similar issues with you recently with my hobbywing.
had contact with some water.
the mt-4 throttle become non functional.
the car cannot move forward with the green led always on with beep beep sound.
brought it home and place of table.
the car jerk forward so hard that my plastic table map was damaged badly.
then after a few recalibration.
as well as total reset of the mt-4.
everything was back to normal.
guess i was lucky.
so scare of water now.
(btw, mine is brushless)

Hmm strangely familiar. I swapped the faulty HPI SC-15WP with another Axial AE-2 and things work perfectly. Now I am convinced the ESC is damaged. Tried opening up but there is a thick black silicon like compound sealing everything under the hard casing. Tried to peel some but it was brittle and broke into pieces. Stopped messing around with it for now coz had to cut the connecter to the receiver to bring over to the AE-2 replacement.. lol  
Will revisit the faulty ESC when i can buy and replace the connector to the receiver.

Kinda like the AE-2 now since I don't have to press reverse twice to reverse..