{"product_id":"oem-lennox-blower-speed-relay-kit-40k58","title":"OEM Lennox Blower Speed Relay Kit — 40K58","description":"\u003cp\u003eThe Lennox \u003cstrong\u003e40K58\u003c\/strong\u003e is a genuine OEM indoor blower speed control relay kit (assembly \u003cstrong\u003eLB-58773DB\u003c\/strong\u003e) that switches the indoor blower motor between heating and cooling speeds. It ensures the fan runs at the correct airflow for each mode, protecting comfort, efficiency, and equipment life in your Lennox air handler or furnace.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCommon failure symptoms:\u003c\/strong\u003e When the \u003cstrong\u003e40K58\u003c\/strong\u003e relay fails, you may notice the blower running at the wrong speed, a fan that will not start, weak airflow, a blower stuck on high or low, or chattering and buzzing from the relay contacts. Pitted or welded contacts and a burned-out coil are the usual causes.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e This kit is matched to the coil voltage, contact rating, and wiring configuration of Lennox blower systems. Installing the genuine OEM \u003cstrong\u003e40K58\u003c\/strong\u003e ensures proper speed switching, prevents motor overload from incorrect ratings, and maintains factory airflow specifications. Generic relays often carry mismatched ratings that lead to premature failure or motor damage, so an exact OEM match is the safe choice.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081079898483,"sku":"LNX-40K58","price":24.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-relay-fan-LNX-40K58.jpg?v=1783759465","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-blower-speed-relay-kit-40k58","provider":"National HVAC Parts","version":"1.0","type":"link"}