When the outside temperatures drop below 40 (I live in Southern Virginia so this is not all that often) the starter will not engage. I have full power from the battery however no starter engagement. NO click at the turn of the key, no sound. Here’s the kicker, as soon as the temperature begins to rise the car will start right up. For instance currently during the “cold snap” we are experiencing, the car will not start or engage in the morning, so I drive my mustang instead to work. When I get home around 4-5pm the Jetta starts right up and has no more problems for the rest of the evening while I run errands. I can drive to another location, go about my business, come out and the Jetta starts right up. Then the next morning, I have the same starter issue. I’m thinking it’s a relay or starter solenoid. Anyone else having this issue or have any suggestions?
I’m thinking that you just have a simple problem with the cables. Remove, inspect and clean both the + and - at both ends. You might want to peel some insulation to get a look underneath too. Make sure it’s all shiny copper and not gunky and chalky looking. Make sure the connections go back on good and tight and see where things stand. Don’t go by what anything “looks like” - you can’t tell by visual inspection.