In the engine compartment fuse box thear are two studs that connect to the positive battery terminal it seems corrosion seperated this conection. can this be replaced.

There may come a time when you try to start your vehicle...and nothing happens. In those situations, a dead or discharged battery is often the culprit.
There are a couple of ways to check: If the starter clicks or makes no sound, and the headlights are dim or don't turn on at all, chances are it's the battery.
Thankfully, jump-starting a vehicle is easy. All it takes is a set of jumper cables and another running vehicle, and you'll be on your way.
Before you start
There are a few things you should do before starting step 1:

• Read the safety, jump-starting, and roadside emergency information in your owner's manual
• Have your roadside assistance number handy

Locate a pair of color-coded jumper cables and a wire brush for removing battery terminal corrosion

Find each vehicle's battery: They can be under the hood or in the trunk

Remove any metal jewelry like rings or bracelets to avoid accidental shocks while working near the battery

Don't disconnect the disabled battery-it could damage the vehicle's electrical system

1. Move the boosting vehicle close to, but not touching, the vehicle with the dead battery so the jumper cables can connect without being taut. Put both vehicles in Park or Neutral, turn off their ignitions, and set their parking brakes. Turn off or unplug all power-draining items: lights, electronic accessories, and portable devices plugged into auxiliary outlets.
2. Open the hood or trunk and remove any battery terminal covers. If you see chalky corrosion on the terminals, remove it with a wire brush terminal cleaner.
3. Clamp the red positive (+) cable onto the disabled vehicle's red positive (+) battery terminal.
4. Next, connect the other end of the red positive (+) cable to the booster vehicle's red positive (+) battery terminal.
5. Now connect the black negative (-) clamp to the booster vehicle's black negative (-) battery terminal.
6. Connect the other end of the black negative (-) cable to a large, unpainted metal surface in the disabled vehicle's engine bay, away from the battery and the engine itself. Make sure the cables are clear of any moving parts.
7. After a final check, start the booster vehicle. Then try to start the disabled vehicle: Usually it will start right up, but it may need to charge for a few minutes before starting. Once it starts, allow both vehicles to run connected for about three minutes.
8. Without turning off the jump-started vehicle's engine, disconnect the cables in the reverse order that they were attached, and close the hoods/trunks.
9. Allow the jump-started vehicle's engine to run for several minutes. Depending on how discharged it is, the battery may not be able to start again under its own power, so keep it running until you reach your destination.
10. Visit your local Ford Dealership as soon as possible to get the jump-started battery tested or replaced.

Use a Delco SI 15 self exciting 100amp alternator....Run one 12 gauge wire from the positive terminal on the back of the alternator, to the positive terminal on the starter solenoid, piggy backed with the positive Battery wire.....All power for any additional functions should pick up power at the starter terminal.....All additional circuits should be fused as well......Always disconnect negative battery cable when working with circuits to avoid arcing and damage to diodes in the alternator............

Did you check the fuse , relay ? Backup Lamps
The B/U LAMP fuse in the RH I/P fuse block supplies battery positive voltage to the switch terminal of the backup lamps relay. The DIC/RKE fuse supplies battery positive voltage to the backup lamps relay coil terminal. When you place the gear selector lever in the REVERSE position, the powertrain control module (PCM) sends a class 2 message to the body control module (BCM). When these conditions occur, the BCM energizes the reverse lamp relay control circuit, closing the switch contacts, the current flows from the reverse lamp relay switch to the backup lamps. The backup lamps are grounded at G302.

Open the rear compartment. trunk lid
Remove the wing nuts from the studs on the rear compartment lid applique.
Remove the rear compartment lid applique from the rear compartment lid.
Remove the backup lamp sockets from the rear compartment lid applique, turning counterclockwise.
Remove the backup lamp bulbs from the sockets.

in engine compartment ,fuse box list on the lid , may be directly on the positive battery terminal , ignition switch fuse interior fuse box lower dash drivers side list on the lid/cover

Below is the procedure for an Aston Martin Vantage, perhaps the vanquish is similar?

Removal
1. Power the driver's fully forward.
2. Remove rear compartment cover.
3. Loosen and disconnect battery terminals, earth (- ve)
terminal first.
4. Release rear carpet, studs (x2), move carpet aside.
5. Remove screws (x2), battery compartment cover to
support rail.
6. Remove nuts (x2), battery compartment cover to body.
Remove cover.
7. Remove Torx screws (x4), remove battery clamps (x2).
8. Disconnect battery vent tube.
9. With assistance, remove battery.
Installation
1. Clean battery tray and clamps.
2. With assistance, install battery into its compartment.
3. Connect battery vent tube.
4. Position battery clamps (x2), install and torque tighten
Torx screws (x4).
5. Ensure battery vent tube is not distorted by battery.
6. Install battery terminals, tighten terminal nuts to correct
torque.
7. Install battery compartment cover, install and tighten
screws (x2) and nuts (x2).
8. Position rear carpet, secure with studs.
9. Install rear compartment cover.
10. Reposition driver's seat.
Courtesy of pistonheads.com

Please vote if this helps! Thanks, Mike

Removing the Starter
1. Step 1 Open the hood to access the engine compartment. Disconnect the battery by unscrewing the positive and negative terminals. This will prevent the risk of electrical shock.
   
2. Step 2 Crawl under the passenger side of the truck and locate the starter. The starter is positioned between the transmission and the engine.
   
3. Step 3 Unbolt the negative and positive wires from the starter with a socket wrench. Take the nut off the stud and pull the wires off the stud. Repeat the same for the positive wire.
   
4. Step 4 Unscrew the two bolts holding the starter to the frame. Wiggle the starter to work it free from the flywheel.
   Installing the Starter
5. Step 1 Position the new starter onto the frame. Tighten the bolts to secure the starter in place.
   
6. Step 2 Unscrew the nut on the positive stud and push the positive wire down on the stud. Tighten the nut on the stud to secure the positive wires.
   
7. Step 3 Unscrew the nut on the negative stud. Push the negative wire on the stud and tighten the nut to the stud to secure the wire.
   
8. Step 4 Connect the battery cables to the terminals. Ensure the positive wire connects to the positive terminal. Ensure the negative wire connects to the negative terminal.
   
9. Step 5 Start the truck to ensure the starter is functioning correctly. The starter should catch as soon as you turn the key and start the truck.
   

2004 Jeep Liberty 4WD 3.7L MFI SOHC 6cyl
Starteer - Removal & Installation

2.4L & 3.7L Engines

1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
2. Disconnect the negative battery cable.
3. Remove the starter mounting bolts.
4. On the 3.7L engine, the left side exhaust pipe and front driveshaft must be disconnected.
5. Disconnect the starter solenoid harness connections.
6. Remove the starter.

To install:



Fig. Starter mounting: 2.4L engine



Fig. The starter position for the 3.7L engine

1. Connect the starter solenoid wiring connectors.
2. Install the starter and torque the bolts to 40 ft. lbs. (54 Nm).
3. On the 3.7L, the left side exhaust pipe and front driveshaft.
4. Install the negative battery cable and check for proper operation.

2.8L Engine

1. Disconnect and isolate negative battery cable.
2. Raise and support vehicle.
3. Disconnect solenoid wire connector from solenoid terminal
4. Remove battery cable from stud on starter solenoid.
5. Remove 3 starter mounting bolts.
6. Remove starter from transmission bellhousing.

To install:

1. Position starter motor to transmission housing.
2. Connect battery cable solenoid terminal wire harness connector to connector receptacle on starter solenoid. Always support starter motor during this process. Do not let starter motor hang from wire harness.
3. Install battery cable eyelet terminal onto solenoid B(+) terminal stud.
4. Install nut securing battery cable eyelet terminal to starter solenoid B(+) terminal stud.
5. Refer to torque specifications.
6. Position starter motor and install 3 bolts. Tighten 3 bolts in this sequence: top bolt, bottom bolt, middle bolt. Refer to torque specifications.
7. Lower vehicle.
8. Connect negative battery cable.

Also can review the Service Repair Manual for Jeep KJ Liberty

I really hope help you with this (remember rated this help) Good luck.

The fuse is located in the engine compartment buy the battery. Under the fuse box cover is the information you need to look for which fuse you should pay attention to, keep in mind that the fuse box in the engine compartment is know for corrosion so pay attention to the fuse box it self for corrosion. The fuse may be fine but the terminals that the fuse goes in to may be damaged by corrosion. Good luck and hope this helps, keep me posted. Be glad to help you get your van running with lights again. 

first, check battery voltage with engine off. It should be @ 12 1/2 volts.
With engine running, it should be @ 14 volts.
If yes, then check for a bad connection at alternator. Look closely at the terminals for corrosion.
There should be BK/DG wire supplying charging amperage to the battery. It does not go through a relay.
Check the mega fuse (175 amp) in the battery junction box (ride side or engine compartment I think). check connection 122 & 197 in same area. good luck

Look if You start the car and wile car running idling, disconnect the positive terminal on the battery and the engine stops, You need a New Alternator, look on the fuse box on the engine compartment for a fuse or a Relay with the alternator name, the main fuse is bolted to the fuse box, but I doubt is a fuse