So I get in my truck this morning at about.... 11:00am or so and its about 45 degrees out. Turn the truck on and it starts up. Turn the heater on and the engine and electrical die. Completely dead. Do this again twice. Give up and keep the heater off. Drive to my grandmothers and start it up again after 5 minutes of turning it off and turn the heater on and it turns on fine. Runs great. I was wondering what might have caused this kind of odd behavior. I'm going to hit a 120k tune up tomorrow. Spark plugs, wires, distrubutor cap and rotor button. I've made a post somewhere here about that.

 

hmm the heater could be drawing to much power in some way and that takes the rest of the power for other stuff and it dies. not to sure its just a guess

 

Is it only when you turn on the fan with the temp in any location (heat or A/C) or is it only when you have the temperature to heat?

What happens if you unplug the A/C compressor (thinking that it might be seized)? But you say that all electric to the vehicle goes completely dead??... Even a short wouldn't cause everything to go dead unless it was permanently dead (ie. not coming back)...

 

I couldn't tell you. This seems like a once in a lifetime thing. Although I am sure the way I turned this on was: Start engine, buckle belt, turn switch to vent, turn level to heat, and I think I moved the fan control to hi. At which point, it died. I do usually leave my phone charger and FM transmitter plugged in over night but it has seemingly no effect on the battery level and start up.