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Q: Doesn't start when it is cold out

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My truck doesn't want to start when it's cold. I try to start it but it doesn't turn over. It'll start with no problem when it warms up. My car has an automatic transmission.

A: Hi, thanks for writing in. Electricity is h...

Hi, thanks for writing in. Electricity is heavily dependent on temperature and other atmospheric factors. Temperature being the most important. Most of the time this sort of problem occurs when the vehicle is hot though. Either way, the diagnosis is the same process. The first thing to do is test the battery as it is the most affected by temperature. The best way to test a battery is with a load tester, (carbon pile or other machine) and a hydrometer which is a measurement of the weight of the battery fluid in comparison to distilled water.

Once the battery has been thoroughly tested, replace it, charge it or continue to the next stage if it is good. A simple test is to tap on the starter while someone is attempting to crank the motor. If the starter takes off, you need a starter. The brushes inside the starter will stick and tapping on it will free them.

With no crank conditions, it is always a bad connection. The question is where is the bad connection. An easy trick to locate it, if electricity is flowing at all, if it is not, this won't work, is to hold the key in the crank position for at least thirty seconds. Sometimes less, sometimes more. If some electricity is flowing in the circuit, the connection that has high resistance will become hot. Even if this connection appears good, it is not and a thorough cleaning with sand paper is often all that is necessary. Check the battery posts, the connection at the starter and the positive battery cable. These are the most common culprits for this.

If you have come this far, you will now need a wiring diagram and a test light. Maybe a multimeter, but that takes some experience to use effectively. If you haven't done this sort of diagnosis before, I recommend booking an appointment with one of our technicians for a Car is not starting inspection

Good luck!

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