Beast5spdGTA

Car works fine with headlights, wipers, radio etc. and will sometimes idle decently with blower motor ~9 volts, vs. 11-12 volts with all other accessories.

However when driving trying to accelerate with the blower motor on, the tach cuts down to 1000rpm or less (from 2000-3000) and car bucks and stumbles violently. Voltage will sometimes cut in half also.

Is this the blower motor grounding out?
Will simply replacing the blower motor fix my problem? BTW the blower motor was replaced ~3 1/2 years ago.

Or is this a resistor problem? It seems to be worse in the 2 highest fan settings, but causes drivability problems in all settings.

Beast5spdGTA

Replaced the blower motor thinking is was just creating too much of a drain. Not the problem.

With blower motor on any fan speed other than the lowest, the car will not accelerate. Turn the fan on med and floor it, car acts like it hits a rev limiter, pops, studders and tach drops from ~2000 rpm to 500 or less. Switch the fan off (while still WOT) and car picks up and accelerates like normal.

Being winter in FL, it hasn't been too bad, but I want my A/C back and sometimes the heat would be nice too. As you can see I've had this problem for a while.

Keep in mind, A/C, Heat and blower motor work fine, just the engine won't accelerate with the blower motor on.

Thanks, please suggest anything to try/look for.

TJQIROC

iTrader: (1)

From what it sounds like, you have a weak alternator. With the car running, your voltage should read 13 to 14 volts. It seems with the fan on high, the volts drop to 9 volts, messing up the ignition. I'd get that checked out.

Beast5spdGTA

Would the blower motor pull more current than say the headlights and/or both radiator cooling fans?

Could I try putting in a lower amp fuse (like 5 or 3) for which ever one runs the blower motor and see if it pops, showing excessive current draw.

I kinda think it has something to do with a large current, but at 3000 or 4000 rpm I'm sure the alternator can output what ever current it would take to melt wires or pop fuses.

I'll try and see if the voltage drops even at a cruise rpm, didn't think of that.

TJQIROC

iTrader: (1)

You shouldn't have to change any fuses. If the fan was drawing too much amperage, it would blow the fuse. The electrical system is designed to run with all electrical components working at the same time, think a hot humid thunderstorm with the AC on high, windshield wipers on high, with the headlights on. With just the headlights and heater on high, you should still show 12 to 14 volts at just above idle. If not, you have a weak alternator. You might invest in one of those volt meters that plug into the cigarette lighter. That way you can confirm the voltage readings. The dash gauge can be way off.

Beast5spdGTA

I'll check the gauge vs. multimeter across the batt. but I think it's pretty accurate.

~14 volts(2nd line past 13 volts), while engine sputtering and poping (just like a rev limiter) until the blower motor is shut off. No change in voltage is what I'm saying.

The idle voltage may just be b/c of underdrive pullies and increased load of blower motor.

TJQIROC

iTrader: (1)

Thats about all I can think of. Maybe someone else could chime in with some insight.

Jono4820

iTrader: (1)

I know this is an old thread but what did you find?? I am suddenly having similar issues while running my air conditioner with fan switch on 3rd position. Car died 3 times after stopping at stop signs. Car started back up as if battery was really low. Battery volts 12.75 when car off for 12 hours. Alternator output 13.80 volts when running lights and air. Car not daily driver battery 3 years old alternator 3 years old.

travis401

iTrader: (1)

The OP hasnt logged in since oct of last year, chances are hes not around anymore to answer your question...Id take the bat and alt and get them tested.