ABS light on in the rain

[Oboscribe]

I've a 2012 650 that now has 20000 miles on it, great bike.
A fault has developed that I need to sort, and it goes like this.
In dry weather, the bike is 100%, no matter what.
Riding in the rain, within maybe 5 miles at the most, the ABS light comes on yellow, and I have no ABS function on the front or rear brake. If I switch it off and then re-start, the light returns within 2 seconds to maybe a minute.
If I leave the soaking wet bike in the garage, by the next day, if it is dry, it is 100% OK again straight from the off.
Today, a development.
I rode 30 miles to work in the dry. Parked it outside, it then rained all afternoon. Got on to ride home on a wet road but when not raining, and within half a mile, the ABS light came on. I hadn't got over 25mph at that point, and I was still dry, there was a tiny bit of spray from the tyres, but the bike was to all intents, dry. Speeds then went up, the roads got wetter, it didn't actually rain, but the light stayed on (or came back on after a re-start) the entire journey.
Obviously water-related, but where? 

[wurzel]

My guess is a rotar sensor on the back or maybe front wheel, or associated wiring in that area  is causing the issue.

[kwackboy]

If you are losing your abs completely (front & rear) I'd suggest it's not either of the sensors as I'm pretty sure the pump has separate chambers for front and rear operation.
I'd look at the loom connector wires that power the pump. 

[Oboscribe]

OK so it's been a couple of years, but I don't ride this bike much, and even less in the rain. I bought an ABS diagnostic plug in thing of fleabay and it tells me every time I test it (when the ABS light is on after getting wet) that it is front sensor failure. I've tried cleaning, removing, inspecting, wrapping  with loom amalgamating tape, no change, always get the same failure as above. Nothing for it but to spew £150 on a new front sensor.
I really don't feel like it is the root of the problem though...

[Ianmc]

+1 for the connectors on the pump.The pump is just in front of the rear wheel, so if there is a gap for water to get thrown off the rear wheel into the ABS area, sods law says it will.Look in particular at the connector with the white wire with a red tracer and the black wire with a red tracer.They are the pair that come from the front wheel sensor.

[UK_Vstrom650]

I read a post last week on Stromtrooper (no 16 in the thread) which suggested the issue could be in the main loom near where it crosses the frame. That started with intermittent faults with the abs when riding in the rain. I've also had issues with the loom in that area albeit not abs.

https://www.stromtrooper.com/threads/abs-problem.431447/#post-5510771

Following on from Ianmc, unless you ride off-road consider fitting a hugger to protect the ABS unit from spray esp if the bike is ridden all year.