Does anybody know where the grid heater can be disconnected? I have pulled off the blue wire off the passenger side battery terminal. That single wire goes into two wires that go to the two relays below the battery that I think is the grid heater relay, but the heater still cycles and I can hear the relay clicking off after heating and the yellow light goes off on the dash.

 

I deleted mine and took both cables off.

The ECM will still make the voltmeter show a voltage drop, even when you don't have it hooked up...

 

two separate codes is set off by the heaters. the first during the wait to start time the ecm looks for a voltage drop, if you simply do not wait to start, no code is thrown. there is a fuse-link in the wire from battery to the solenoids, just remove the link. now remove the wires to the grid and the grid. the second code is set off if you remove the wire that feeds the solenoids from the ecm, the ecm looks for the coil current draw. most leave them connected, I though on the 03 it was a green 18 gage wire, we prefer to remove them and connect a 24 ohm resistor in there place