Alternators

If your battery is totally drained, the car will fail to start. You may be able to "jump-start" the car using another vehicle. But why is the battery dead? If you left the lights on, even a small dome light inside the car, that could have drained the battery. Jumping the car and then letting it idle for a while can replenish it, but if the battery is old and near the end of its service life, it may not be able to take and hold a charge any longer.

Or the problem could be the alternator. Perhaps it is no longer able to recharge the battery. If that's the case, the battery -- even a brand new one -- will eventually run down, and rather quickly, because your car's electrical system will be running off battery power, instead of from power supplied the alternator. When the battery goes dead, your vehicle will stall, because there is no power to run the electrical systems.

This might have worked on a car thirty or more years ago but is actually potentially very harmful for a modern car. The cars now are designed to have a battery as an integral part of the charging system and if it is disconnected can send voltage spikes through the system and burn out your computer. Also the alternator is designed to put out a certain amount of current and this test would only tell if the alternator is putting out enough current to keep the engine running, not if it puts out enough to keep the battery charged, run the lights etc. The only real way to tell if the alternator works is to put a voltmeter on the battery and see if the voltage goes up after the car is started. Then to tell how well it works, put an amp meter in line with the alternator and see how much energy it puts out when the various circuits are turned on.

A bad battery can be hard to detect sometimes. It can work fine then all of a sudden fail to start. Then next time you try it works fine again. The best way to test it is with a load tester at an auto parts store or shop.

ERROR: A voltage is applied to the rotor winding by way of the slip rings. This creates an electro magnet who's field cuts across the stator windings. The stator winding voltage is an alternating current that is retified and regulated and is outputed out at the terminal on the back of the alternator. This is exactly the reverse of the above. If the above were true the brushes would smoke when a high current passed through them

ALTERNATOR WARNING LIGHT

"What does that little red light that says ALT mean when it comes on?" Very basically, it means that either the alternator output voltage is lower than the battery voltage, or the battery voltage is lower than the alternator output voltage. If the light gets dimmer as you rev up the engine, then you most likely have a problem with the alternator. If it gets brighter, then the battery is most likely bad.

That's all well and good, but just exactly what does all that mean? To get a good idea, it is first necessary to understand how an alternator works. You don't need an engineering degree, just a basic understanding of the general principles. Figure 1, below, is a block diagram, or a "functional" diagram, of an alternator, and its connections to the remainder of the automobile electrical system. Following the figure is a description of the various components that make up an alternator, and a description of how each operates to keep the battery charged in your car.

That's all well and good, but just exactly what does all that mean? To get a good idea, it is first necessary to understand how an alternator works. You don't need an engineering degree, just a basic understanding of the general principles. Figure 1, below, is a block diagram, or a "functional" diagram, of an alternator, and its connections to the remainder of the automobile electrical system. Following the figure is a description of the various components that make up an alternator, and a description of how each operates to keep the battery charged in your car.

That's all well and good, but just exactly what does all that mean? To get a good idea, it is first necessary to understand how an alternator works. You don't need an engineering degree, just a basic understanding of the general principles. Figure 1, below, is a block diagram, or a "functional" diagram, of an alternator, and its connections to the remainder of the automobile electrical system. Following the figure is a description of the various components that make up an alternator, and a description of how each operates to keep the battery charged in your car.

• See "Related Questions" below for more specific details on the DOHC alternator replacement procedures
• Many repair shops and auto parts stores offer inexpensive or free alternator & battery testing.

  Be sure to test before replacing!

• If you have the engine with the dual overhead cam it is not easy, I just did it and it took me 12 hours.

3.0 12 valve, Vulcan engine, the alternator is on the top in the front.

• Release the serpentine belt tensioner and remove the belt
• There is one wire bolted to the alternator and one plug in - remove the wires
• Loosen and remove the bolts (three bolts)

3.0 DOHC (dual overhead cam) 24 valve engine

See "Related Questions" below for more specific details on the DOHC alternator replacement procedures

• Lift and chock the rear wheels
• Remove the passenger-side tire
• They tell you to remove the steering arm, but I have been able to get it out without doing that.
• Release the belt tensioner and remove the serpentine belt.
• You must then reach up under and undo the wires (one bolted on and one plug in) and
• Still working from through the wheel-well, remove the two bolts from the bottom and one from the top.
• If you twist the alternator around as you drop it you can usually get it out without undoing the steering arm.

BEFORE YOU GO THROUGH ALL THIS TROUBLE!

There is a mega-fuse on the front of the fuse box under the hood. It has a positive and negative wire bolted to it, remove the bolts, pull the fuse out and shake the little tabs to see if they are loose.

If they are loose it will cost you $4.99 for a new one at Autozone.

Find belt tension idler arm and release belt making sure you draw a picture or check to see that there's a routing diagram of how the belt goes and then you need to locate the upper and lower bolts for the alternator usually one on the top ear and one on the bottom ears, then disconnect harness and ground wires and repeat in reverse order. Hope that works. for you.

first disconnect the battery for safety. unhook all wire connections to the alternator (i think there is two of them). loosen the two bolts on the alternator that secure it to the engine. put a long pry bar on a wrench on the bolt for the alternator belt tensioner, making the belt loose. then remove the alternator (it may be in tight and require some strength). install new one in reverse order.

I own a 1997 Mercury Sable Station Wagon, and did own a 1992. The alternators look to be in about the same position on both cars which have the 3.0L engine with standard overhead valves, right up top and easy to get to.

First, undo the cables on the battery posts. Then "unsnap" the electrical connections on the alternator, and unscrew them.

Now you don't really have to, but I'd advise it because it makes everything so much easier and gives you room to work. Remove the radiator over-fill tank, after the car has sat cooling for a while. First compress the rubber hose clamps with a pair of large pliers and pull the rubber hoses off. Channel Lock pliers work good for that. Those hoses will be fused to the metal fittings by the heat, but, gently twist them back and forth until they come off. A dab of dish soap inside the rubber hose ends will make installing them back on much more easy.

The over-flow tank is the large white plastic tank on the passenger's side of the engine compartment that blocks your sight and access to the belt, pulleys and bolts. Plug all the removed rubber hoses, and white tank nozzles, with compressed paper towels with Saran Wrap rubber-banded around the "open" ends if you don't want anti-freeze and water all over the place.

Relieve the pressure on the fan belt, turning clockwise with the bolt on the automatic adjuster (Tensioner) and remove the belt. I use a 15mm box wrench with the open end "ground down" to fit inside one of my floor jack handle extensions because it a little too tight to get a large socket wrench and socket in there. But a long "breaker" bar with a 15mm socket on it might work too.

There should be a diagram on the underside of the hood as to how it goes back on, plus it will also show you what each part on the belt is.

Remove the three smaller nuts that hold a top upside down "Y" bracket on the intake manifold and alternator then the two long large long bolts holding the alternator in place. Install it back in the same way you took it out.

The two large long bolts should be snug, about 25 foot lbs, or "tight" and then 1/4 of a turn tighter, if you don't have the wrench to check the tightness. The smaller nuts just hold the top "Y" bracket and should just be very snug.

Put everything back together the same way and order you took it off and it should work fine.

Go to autozone and pay the $16 for a Chiltons repair manual for your car. It gives a play by play with pictures. There are only three bolts, one nut and the cables to disconnect. Just be sure and unhook the negative cable from the battery first.Its mounted on the same mount as the PS pump.

Disconnect the battery, remove the right side wheel, remove the dust covers inside the wheel well, loosen the engine and transmission mounts and with a floor jack place a piece of 2x4 wood on the floor jack to protect the engine's oil pan, and lift up the engine just enough to squeeze the alternator out through the wheel well,

If you're looking for the alternator, and don't know what it is, chances are you probably shouldn't be messing with it. However, it is located on the very top of the engine, on the passenger side. You'll see some vents in it, in which you can see many copper wires woven around inside. Not professional directions, but it'll get you close.

you have to take off the left driveshaft from the tranny so make sure you drain it first, be careful when taking the shaft off if you yank it off too had you can damage you cv joints, the you have to take off the belt, then unbolt the alternator mount and unbolt the alternator. you will have to take the driveshaft off from the where the wheel is so u need a crobar to wedge in the lug bolts so the tire doesnt turn while you loosen the bolt

PS: This method works easily with a couple of extra hints. 1) Don't forget to disconnect the negative cable in the first place. 2) Secure the strut as far down and back as it can go. I pushed it down with my foot while reaching under the fender to wedge a stick about 10 inches long between the strut and the wheel well. 3) Remove the single bolt securing the motot mount nest to the fender and dismount the electrical connector from the radiator fan bracket to give room for the engine to be levered forward. 4) Lever the engine forward with a long crowbar placed between the driveshaft and the oil pan. With the alternator positioned as above you can wiggle it out by hand and shove the new one in with your foot. This works so well I didn't get too depressed when I realized I had bought the wrong alternator and had to do this all over again. Do compare your new alternator to the old one before you install it. The difference is that carb models have a three-wire connector and fuel-injected models have a four-wire connector.

I know a mechanic who swears by disconnecting all the motor mounts and BOTH CV axles, then using a transmission jack to pick the engine up about an inch and a half. This works very well--it opens a gap between the bottom of the engine and the back of the engine compartment wide enough for the alternator to slip right through.