The air conditioning switch assemblies don't fail very often, but when they do, the only way to fix the problem is to replace the unit. We have new factory units available for most Mercedes® models and even rebuilt units if they are obtainable from our vendors. Please note on rebuilt units there is a refundable core charge. Returned cores must be in rebuildable condition, without any broken/missing/melted plastic components, and must not have the electronics tampered with. Cores must be returned within 30 days of purchase to receive refund.