Heater causes rpms to drop

[Zexell]

Whenever I turn on my heater, my rpms drop dangeriously. If im at a stoplight with my heater on, my rpms will drop to around 100-200rpm and i get very low power voltage. high 11 volts or low 12volts.

Normally, i'm at around 600rpm and 13-14 volts. It only does this when i turn the fan knob. Is there too much load?? What could be causing this?? Would doing a ground kit help???

 

[1320Motorsports]

Have you ever replaced your alternator? I've had a lot of trouble with aftermarket replacement alternators, not putting out enough power under load. Thats the only thing I can think of that would cause that.

Matt

 

[Zexell]

Yea, i guessed the alternator is going out on me by now.

A friend suggested that I bump up the idle by 200-300 rpms to compensate for the load. Is this ok?? This would mean that I'll be at 800-1000rpm at idle.

 

[Do_You_Has]

My rpms are normally 800, with the heater/AC it drops to 500, unless it decides to idle surge on me, then it goes up to 1900.
but 100-200 sounds dreadfully low...

 

[Nanan]

Well you either have one or a combination of the following, bad alt, bad battery, bad ground. It wouldnt be a far strech to see the engine drop 100 or so rpm when the fan goes on full blast because that is a serious amp draw which will both starve power from the coils and force the alternater into high mode.