Switch on car

All I can do is look up your battery specs. It shows 600 cca @0 degrees f. for trailer tow package.
There are batteries with larger cold cranking amps, I just don't know if they will fit in your vehicle?
Park the vehicle in a heated garage or at least out of the wind, if possible. You could try a block heater, see if that helps? Your oil viscosity might make a difference.

https://s27.postimg.org/yy2w2qx43/starter_motor.jpg

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Are you talking about starter motor? In the diagram, see starter relay, unplug the relay, see terminal 30 and terminal 87, if you use jumper wire between those two terminals, the starter motor should crank, Terminal 30 is hot all the time. If you try this make sure tranny is in park or neutral and parking brake is set. If it cranks with the jumper, the problem is on control side of relay, ignition switch--neutral switch--or wiring circuit, somewhere. see crank fuse, use a test lite and voltage on crank fuse when problem is ongoing. I can only help with testing.

run fault codes to check for ambient temp sensor problems . check for fuel pressure in the manifold

I have a 2000 pontiac grand prix with a digital climate control system. The heat quit working, it doesn't blow out any heat. Now that it is warm outside the air stopped blowing out any air. The digital temperature on the climate control is not correct. When it states that it is below 30 degrees on the ext and it is warm outside the air wont be cold. Once it starts going above 30 degrees the air gets colder. Today the blower stop working all together. Was told it maybe the climate control unit was bad. You can hear the door opening/shutting when you switch the temp from cold to hot. But there was no heat blowing out whatsoever in the winter time. Could you please give me your opinion on whether or not it is the climate control unit or something else?

sounds like starter crank sensor will turn over but will not start

When your car is warm, everything is at its maximum expansion. Sounds like an overheating issue. But again I am not there to inspect and diagnose it. It could be several things. Winter driving keeps your engine way cooler than summer heat

you need to have the engine coolant switch checked,since the computers rely solely on sensors,the ect tells the computer how cold or hot it is so the computer will make it a rich or lean mixture to start the engine,if it tells the computer that it is 75 degrees the computer will lean the mixture like starting a car in the winter without a choke.

If plugs, wires, and battery is new and good, make sure you are using 5w30 oil which is thinner and is made for winter. If needed, replace the fuel filter. There is a cold start valve that may be giving you problems. You can go to autozone.com and register for full free online repair manual for your car.

I have the same problem, except this happens below 29 degrees. If jiggling keys dont work. I loosened the steering wheel adjusted and banged it up and down a couple times it worked every time so far. also the engine stopped 3 times while driving on interstate, restarting worked. this is a 2003 tdi with 90k miles on it. I am not going to try to repair until next winter. if the problem comes up. i will replace starter key switch. I think is has something with cold and wireing retracting when cold.

possible coolant temp sender or crank sensor,have you got fuel at the plugs and a spark,one quick check is to disconnect the temp sender this will then put it into a cold start fuelling....