can a faulty grid heater kill the batteries in a truck? is that a high amp draw from the batteries to heat the grid heater? i suspect i might have a bad one.

 

The battery voltage goes through a relay before it gets to the grid heater. Actually there are two relays and two battery wires going to the grid heaters. If the grid heater is draining the battery it would mean that atleast one relay is stuck in the closed position. This is not impossible but they usually fail it the open position. How long does it take to kill the batteries? You can check this with a test light or volt meter. Shut off the truck, unhook the wires from the grid heater, and test for 12 volts or if the test light lights. If you have 12 volts or if the test light lights the relay is stuck in the closed position and you need new relays. If you do not have 12 volts or the test light does not light your draw is somewhere else. Make sure you unhook the wires that come from the relays and do not touch them to ground incase they are live.

 

Thank I Will Check That.

Very Possible I Have Been Doing Alot Of Driving In The Sand So It Could Just Be Full Of Sand In The Relay.