They can be tested in-situ and in fact if you remove them, you will no longer have the reluctor ring to generate a signal so they cannot be tested. The sensors themselves are apparently very difficult to get out without damaging them, so the options are to fit new (expensive) or replace the whole h...

it's been suggested that a faulty sensor could be causing the ABS warning light to illuminate. how do I get them off and check. what do they look like etc. any tips greatly appreciated folks

Whilst stocking up on gear from the camping shop for a trip to the continent an assistant tried to advise me to buy a reverse polarity detector, to test hook ups are wired correctly, I suspected opportunist selling, are they needed and if so what use are they?