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Heater Draining battery

Posted by deb_pa (My Page) on
Thu, Jan 26, 06 at 9:48

Hello, my son has a Chevy Silverado pickup with crew cab and full bed. I don't know the year. When he forgets to turn off his heater the battery goes dead. Battery was checked and it is ok and starts ok if you remember to shut off heater when getting out. Battery charges good while running and running heater doesn't affect battery when truck is running. I know, I know, remember to shut the heater off, easier said than remembered. Thanks for any help.

Follow-Up Postings:

RE: Heater Draining battery

The heater fan will run the battery down in about 1/2 hour or so. The voltage to the heater should shut off when the ignition key is in the 'off' position. I don't have a schematic for your vehicle, but most heater fans get their power throuh the 'accessory' connection of the ignition switch, and this eliminates the problem of forgetting to turn it off. However, there are two possibilities for your case:

1. A relay was used to supply the heater fan/blower and this relay is stuck closed.

2. There was a problem in the past and fan/blower was re-connected to a different location, one that is 'hot' at all times.

Check out the connection for the heater fan/blower and correct.

RE: Heater Draining battery-2

Another possibility:

The ignition switch is mis-adjusted and is in the 'accessory' position when the key is removed.

RE: Heater Draining battery

If this is a high mileage old truck, then I can see that the ignition switch could become loose and mis-adjusted, and if this is a GM weakness.
And AM(after market) accessories can also do this battery drain..
Pull the negative cable and test..

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