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Why won't my SLK unlock?

My Mercedes SLK 250 won't unlock. Last Sunday it sat on my drive during very heavy rain and hasn't let anyone in since. The key raises the button but the car remains locked. Both keys have been tested. I've tried various tips from local experts and everyone is baffled (eg giving it five secs plus with the key held close to the handle to send an infra red signal). A mechanic jacked the front up and declared there was life in the battery. I'm about to get it spec lifted to the main Merc deal which my brilliant local garage said was probably best in case they failed to solve the problem. I reckon its to do with water ingress. This might be irrelevant but a few times the aircon hasn't switched on which I also think is after heavy rain. It makes me wonder if some filter is sodden or unseen gutter blocked and could this now be causing the car to lock down?

Asked on 12 November 2019 by David Keates

Answered by Keith Moody
This is a fairly common problem, unfortunately. We spoke to Mercedes specialist the SL shop, who suggested it may be caused by plenum blocked drains that allow excess water into the car via the heater motor chamber. 'Because the electrical connectors and ecu's are below the carpets they are often damaged. The quick check is to get a bucket of water and pour it onto the windscreen and make sure it flows out straightaway underneath the car on both sides. The drains usually exit behind the wheel arch liner.'
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Excellent build quality, terrific engineering and a very good crash test rating. Much better drive from 2000 onwards.

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