If it didn't crank over (dead battery) when really cold but seems OK when the weather is warmer your battery might have lost some capacity. Generally, as batteries age they will lose capacity. When they get cold you get less output so a lower capacity battery might not crank the engine. This same battery would normally start the Jeep fine on warm days. You could get the battery tested - Sears used to to it - and see if it's time to change it out. There should be a date code on it somewhere. Look for a little round sticker with a letter and number on it - that's your date code. If the battery is older than 4 or 5 years and you routinely get very cold weather it might be time for a new one. If the battery checks out OK you'll need to check the charging system. Also, for cold waether you might consider synthetic oil. It would be better for the engine. Best of luck - John
