On our 2003 for a couple of months now upon initially starting it for the day, whether it is cold enough for the system to come on or warm enough not to bring it on, (the heater light seems to work correctly, stays on if cold enough or immediately out if warm enough) the volt gauge will stay to left of 14V where it normally would be on a cold start. Then the gauge will slowly come up to the 14V mark and starts to go to the right of 14V. When this happens, the "check gauges" light will come on. Then it will suddenly go to the left just on the low side of 14V, light will go out. Then it cycles again and again for awhile with the "ding" and "check gauge" light coming on and off. The longer the drive, it finally settles down to the right of 14V where it normally runs and no light or ding. Watching on a digital VOM the volt gauge is correct. Does anybody have any ideas or know where the grid heater system plugs in or which fuse is for the grid heater system?

 

Your stated indications do not suggest any fault with the grid heater. I would check and clean the battery and alternator connections first. If that does not resolve the problem, get the alternator checked out.

 

Like you I have an '03 and I completely removed the grid heater as in South Texas it is just an obstruction in the air intake. The grid heater is run through a high current relay directly from the battery. Are you sure the Check Gauges light comes on when it above 14 volts and not the other way around? I suspect the check gauges light is from the 'low voltage' due to the high current draw and voltage drop on the battery when the grid heater is on.

If the scenario is as you describe it may be due to the drastic change in battery voltage over a brief period of time causing the 'fault' light to illuminate. Once the voltage remains stable for awhile from your description all seems okay so I do not think you have a problem. Good luck.

L8r,...........dogger