Mon Aug 03, 2020 7:05 am
I think the issue is more likely to be with it not cutting off the motor current when it's supposed to be parking rather than the rain sensor, as it does it on non-auto modes such as single wipe.
You should try a different garage - I don't think there's anything unusual about the Outlander's wiper system compared to most other cars. Ask locally for recommendations for local garages who are good with electrical problems, or find an auto-electrician.
What's needed is a wiring diagram (any decent garage should be able to obtain that - it's not too hard to find unofficial copies on the web). Then monitoring of the voltages on the wires going to the wiper motor, and what's happening with the park switch inside the motor gearbox that should be cutting off the power to the motor when the wipers reach the parked position. I see a few posts back the wiper relays were mentioned - do you know if these were checked? Relays are very easy to test.
2015 Mitsubishi Outlander PHEV GX4H (petrol/electric)
2008 Volkswagen Caravelle (diesel)
(recently departed - 2004 Subaru Outback 3.0Rn (LPG), 1991 Mitsubishi Pajero 2.5 LWB (WVO))