Cold weather causes alternator to not work until warm

JRTFRED · #1 01-19-2005, 12:47 PM

When the car sits in below freezing temperatures for many hours, after it starts, the voltage guage shows 12V and continues to drop until I can get the car into a warm garage or the weather allows the engine heat to remain in the engine compartment. Then the voltage shoots up to the normal 14V. After that everything is fine. Is there something that cuts out the alternator when the car is started and when it's freezing out, sticks until it heats up?

Mikado14 · #2 01-19-2005, 06:37 PM

Have your battery load tested.

JRTFRED · #3 01-20-2005, 09:09 AM

Quote:

Originally Posted by Mikado14

Have your battery load tested.

I replaced the battery to try and remedy the problem. Battery is brand new.

Mikado14 · #4 01-20-2005, 10:02 AM

Quote:

Originally Posted by JRTFRED

I replaced the battery to try and remedy the problem. Battery is brand new.

Since you have tried the battery, the next step is to check the voltage when the engine is cold and see if the alternator is putting out and/or do a load test on the alternator. Remember this, the internal regulator does have electronic components and it could be temperature sensitive, ergo, it is bad, new alternator time.

JRTFRED · #5 01-20-2005, 10:11 AM

Does the alternator normally get cut out of the electrical system while the starter is cranking?

Mikado14 · #6 01-20-2005, 10:24 AM

Quote:

Originally Posted by JRTFRED

Does the alternator normally get cut out of the electrical system while the starter is cranking?

For all intents and purposes, I will say that the field wire is cut out when the ignition switch is turned to the start position. The diode Bridge is not but is normally protected by a diode trio when the starter is disengaged to prevent back EMF from damaging the bridge.

JRTFRED · #7 01-20-2005, 10:32 AM

Is the field wire cut out via a relay or directly through the ignition switch? If it is a relay that can be affected by freezing temperatures, then it sounds like I need to replace that relay instead of the starter.

Mikado14 · #8 01-20-2005, 10:48 AM

Quote:

Originally Posted by JRTFRED

Is the field wire cut out via a relay or directly through the ignition switch? If it is a relay that can be affected by freezing temperatures, then it sounds like I need to replace that relay instead of the starter.

No, there is no relay that I have ever seen. It is done through the ignition switch.

Apparently, you do not have a DVOM to measure the voltage when it is cold. Ask around and see if you can borrow one. It will answer many questions.

JRTFRED · #9 01-20-2005, 10:57 AM

I have a meter, now all I have to do is wait until the temperature drops again ! Thanks much for the help !

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