Battery or Alternator?

1990 Camry. Whenever I open/lock the door using the power door lock button, the engine would cut off. It does not stall or stop, just cut off for an instance. What would likely be the problem, battery or alternator?

Thanks for any help!

Reply to
ZR
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I would guess it is neither. Not to say that it definitely can't be, but an intermittent short is a more likely cause of the problem. Can you make the engine stop running if you hold the door lock button in either open or lock position? Will the engine start holding the button in either position? Does it make any difference if any window is up or down, or the door is open or closed? If you have a volt meter check battery voltage with the engine running (13.5 to 14.7 volts approximately) and with the engine off, (12 to 13.5 volts). A bit more information would be helpful.

Reply to
user

I doubt if the battery or alternator is bad. If the battery or alternator were bad, then turning on the headlights, radio, heater, rear defogger, etc. would have the same effect.

Are there any aftermarket accessories installed like a remote start, keyless entry, or security system? If so, I would check the wiring where those systems are spliced or tapped into the factory wire harness.

Reply to
Ray O

He's right. Besides, if your battery or alternator were bad, you wouldn't be able to start your car.

I don't think it's a short, because if it were, you'd blow a fuse.

I suspect that it is a wiring problem.

Jeff

Reply to
Jeff

Thanks for the info. It does not have the cut-off effect when turning on accessories, but the idle speed does drop a little (noticeable). It does not have keyless entry, remote start or security system. I was thinking maybe the current draw is too much when using the power door button. Would that cause the idle speed to drop too much so that it feels like a cut-off?

Reply to
ZR

It is possible that there is a high current draw when using the power door lock button, but if that is the case, then the problem is more likely to be either a bad power door lock actuator, something binding like a door lock rod or door lock, or bad wiring somewhere. Although I suppose this is possible, I have never seen bad power door lock actuators or something binding enough to affect engine operation. A more likely culprit is a bad switch, relay, or wiring.

Reply to
Ray O

If the current draw were 20 A, then that would be about 240 W (20A * 12 V = 240 W). One horse power is about 750 W. So that means that it would use up around 1/3 HP. That might cause a momentary drop in idle speed. But your headlight draw is probably more and certainly not significantly less.

I really doubt electrical power issues is a problem. Pushing on the bottom probably doesn't cause more than 10 W to be used. It is probably computerized, meaning that there is no appreciable load on the computer (probably takes like 1/1,000th of a second to handle the request). Activating the thing is probably 5 or 10 W draw on the car's circuit and less than 1 sec.

The other thing to realize is that if the current draw is too much, before it causes cutoff of the engine, it will cause cut off of the circuitry -- by blowing a fuse. You'd know this if it happens, I hope.

Jeff

Reply to
Jeff

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