I have had a heater issue for a long time in my '91 Spirit, 2.5L. I turn on the heater, starts generating heat, then it cuts off and the 'Air Bags' light comes on. I turn off the heater and the light goes off. Turn it on again, cuts off, light goes on, turn off, light goes off. I am aware this would be a ground issue but admit I know little about electrical and where to look. Can anyone help me on this with some advice? I don't want to face the winter again with no defrost. I thought it might be my resistor since when the blower switches from off-low-medium-higher-highest it cuts off at the highest setting. I replaced it (mounted behind the windshield wiper fluid tank) put problem persists. I will in summertime turn it on, it blows for awhile, stops, see 'air bag' light come on, kicks back on again for a second, stops again, a couple seconds later comes back on for a second, never really stays on. In the winter when it goes off it stays off until I switch to off and see the 'Air bags' light go off too.