94 Crown Vic Electrical Problem?

My car starts and runs fine, most of the time. Recently, while the AC is on, I've heard a grinding type noise and the car will just suddenly die, usually while idling at a stop light where you really DON'T need your car to die. The car then will act completely dead, and not restart, like the battery is dead...until...one day a police officer used his vehicle to push me to a safer spot, and while I was waiting for assistance, I tried to start and the car suddenly started. Another time, we tried jumper cables and after a bit of time the car restarted.

Any idea what is causing this? Do I need a new battery, fuse or something else? Driving without the AC is not an option as I'm in FL and only one window motor currently works. :-( Help!

I wonder if your a/c compressor is locking up?

do you hear a single click from the starter when you try to start it?

No there is no click upon start up. The car just starts normally. The failure happens during idling, and its like its drained all power from the battery. Then after "rest" or being attached to someone elses battery for about 5 minutes, it starts normally again.

The A/c compressor clutch and fan use high amounts of current when running. The alternator may not be charging while at low RPM's ie: stopped at at a light. The battery will rejuvinate it self after a few minutes, enough to start the engine. I would check the charging system and battery.

thanks, that gives me a place to start, when going to a mechanic. The battery was new Jan of 07, its possible I suppose that I need a new one, but what you said about the charging system (though I don't know what that means) makes sense. Is the alternator part of the charging systeme, or just the end recipient?

Cynthia

The alternator is what supplies amperage and voltage to the battery. wgbtucson is correct about the low voltage at idle. Have you noticed the battery light or charging light coming on at idle?

No the battery light does not come on when all is working fine. I can't recall offhand if it comes on before or after failure. I've just noticed the noise from the AC.

The first sign that I'm about to get shut down is the noise from the AC.

It sounds like you might actually have two problems. The A/C compressor is cycling on the inside comfort thermostat. When it starts, while at a light, the compressor amperage draw is pretty high. If the compressor bearings and valves are damaged the unit will be dragging and run hard. When This happens the alternator and battery may not keep up with the demand. The alternator charges the battery and provides power for the car.

By the way, if you go to a local chain auto parts store like Auto Zone or Checker, they will check the charging system and battery for free. At least they do here in Tucson. Good luck.

Thanks for the tip. :-) I hope its NOT too many problems, since I can't afford to fix any of them right now. I did just tool around in the car today without the AC on and everything ran fine, though it was hot with just the one window open. Speaking of which, that last window is going up and down slowly. The other 3, I can hear the motor working but the widows just move slightly then seem stuck. Any chance they just need lubrication and not new motors? If so, with what and how?

Hi all back again! I was just using the car, without the AC on, and it began making that metal on metal whining/grinding noise. The car stalled out at a light but restarted right away. Given that the AC was not on, would it be correct to assume that the AC may not be involved and that most likely I need a new alternator and/or battery? If so, are there instructions/pictures online for replacing the alternator or do I have to go buy the book? My fiance thinks he can replace the alternator but I'd like written instructions to follow!

OK, not that anyone has been going out of their way to help here...but I'll offer an update anyway.

We went to autozone to have the electrical checked, found the battery was bad so changed that there and he ran the test again, no trouble in the alternator. Whew. So now what? The problem being that the noise didn't occur unless I was driving, hard to tell where it was coming from.

So, changed the belt and tensioner this morning. The car started up and idled VERY rough and lo and behold the noise immediately began. It was, of all things, the housing for the air filter vibrating uncontrollably. The air filter looks ok but I'll get a new one anyway, we took off the hose and checked for clogs and debris, nothing major found. The AC runs now without overloading the electrical now too. Faulty belt, tensioner and battery seems to have been the issue there. So I took the car for a drive to let the computer do its job. The car is running MUCH better with the new belt and battery, the noise still coming from the air filter box though, but not as bad.

I found a note online with someone with the same trouble and will check the air intake next week for a leak, and make sure there isn't a speck of dust in there and replace the filter. Other things to check from what I understand, is to clean the MAF and check, clean or replace the idle air valve. Any input from anyone who has run accross the rattling air filter box problem before would be appreciated.

Oh, and this car is a 1994 but only has 30,000 miles on it. It was my grandmothers and just sat mostly under a carport for the past 15 years. I'm using it now to pull a trailer to and from art shows. Would like to keep it running well for this heavier duty. The trailer is 1200 lbs empty. I put about another 1000lbs in it.

Thanks for the update. Just remember that most people that offer information here have other jobs as you probably have. Diagnosis of noises is close to impossible over the internet. Without hearing them is like asking you to tell me what color my car is. Just don't get too upset over the lack of response to your loast post about 30 hours before this one. I read your post yesterday, but I did not have any more to add to what had previously been stated.

Thanks for commenting. If you'll note though, I asked a few questions back in september that went by without anyone taking note. About my window motors. Thats what I was talking about. I am surprised too that no one suggested a place like autozone for help for diagnosing. I found out about autozone's free help just yesterday. Though it was actually a worker at Advance Auto Parts that thought the belt and tensioner might be the electrical issue, in addition to needing a new battery of course. There was no battery light coming on to show I had a problem with the battery either.

Do you have any answers or insight about either the window motor issues or the air intake/ vibration or did you just stop by to tell me not to get upset about no answers? :biggrin:

Touche' :smile: Saw where you made a small comment about only one window working. As it was down by itself, my thought was you were interested in the noise and running problems. I thought the window was an afterthought. Sorry.
You could remove the door panels and lubricate the motors to see if it might help. Also while you are there, check to be sure the current is getting to the motor. Use a test light with the clamp on a good solid ground(clean metal) and see if it lights up. If it lights up, the motor is the problem. If the light does not work, go to the master switch to see if there is current coming from each switch. If current is coming from each switch, look for a broken wire in the door where the boot is between the door and the body of car. Again, I apologize for the oversight. If you need anymore assistance on the motors, Please start another thread with the window motors as the main subject line.