I had a broken timing belt in my 93 legacy I've taken the old belt off and would like to install the new one but i need the belt routing diagram and also need to know were the timing marks go on the belt

remove belt make sure you have the routing diagram for the belt. Take old tensioner off install new one reinstall belt ,tensioner will need to have tension taken off with wrench take tension off install belt let the tensioner go easily and slowly.

https://www.google.com/search?sxsrf=ALeKk02lTsKtC4FkaLXPemOsjccehu7hhg:1585762938820&q=routing+diagram+for+a+serpentine+belt+for+a+4-cylinder,+93+Ford+Ranger.+The+Ranger+has+A/C+and+power+steering.+Thank+you&tbm=isch&source=univ&sa=X&ved=2ahUKEwjj9qml48foAhWSERQKHQ8uC_gQsAR6BAgEEAE&biw=1473&bih=696

If it a serpintine belt (meaning one belt runs everything) and it comes off on its own its time for a new belt to install new or reinstall old one . All cars have abelt routing diagram if not google your car and year asking for belt diagram. Locate tensioner usually turns with wrench ( socket or box end is best) route the belt according to dia. leave tensioner for last rotate pully with wrench to get belt over release tension on wrench thats all there is to it. But if belt keeps coming off usually indicates new belt is needed could also need tensioner pully its a good idea to replace both at the same time

Go to the following link and the first photo shows the belt routing. I hope this helps as I know changing the belts on these vehicles can be a major pain in the neck.
Pelican Mercedes Benz Tech Article Mercedes Benz Drive Belt Replacement...

Did you compare the new belt with the old one to make sure they are the same length ?
And are you sure you have it routed correctly ?

to replace the serp belt you'll need to release the tensioner in the system remove the old and install the new the issue always is the proper routing for the belt follow the diagram under the hood watch the routing as you remove the old belt if a diagram isn't available under your hood request one upon the purchase of your new belt sometimes the parts store will loan or rent you the tools you need for belt replacement

Hi, when a belt comes off, it's usually because of a bad bearing in one of the accessories or idler pulleys, or maybe your tensioner spring is broken. Remove the belt and check all pulleys for spin and play. It is also possible you lost an idler pulley and the new belt routing is not turning the water pump in the right direction. Check the routing and look for a missing idler pulley. Let me know if you are missing the routing diagram.

The alternator belt on the 1999 Dodge Caravan also controls the air conditioner compressor, the water pump and the power steering pump. The belt is called a serpentine belt, and it is designed to fit around all of the accessory pulleys at the same time. As the belt travels around each accessory pulley, it enables the accessory to operate. Once the belt is damaged, cracked or frayed, you should change it before it breaks. If that happens, each of the accessories will stop working.

Open the hood and prop it up so that it does not fall. Engage the parking brake.

Inspect the top surface of the fan shroud for the serpentine belt routing diagram. Follow the routing instructions on the diagram to install the new belt.

Locate the serpentine belt self-adjusting tensioner on the front of the engine. The tensioner is directly below the alternator. Use the bolt that connects the tensioner pulley to the tensioner arm to rotate the tensioner.

Turn the tensioner device counterclockwise to move the tensioner. This will relieve the tension from the belt. Once the belt has enough slack in it, slide the belt out from under the tensioner pulley.

Lift the belt off each accessory pulley. Slide the belt around the fan blades and out of the engine area.

Lay the old belt next to the new belt to ensure that the new belt is the correct width and length. Slide the belt around the fan blades and around the crankshaft pulley on the bottom of the engine.

Follow the belt routing diagram to position the belt around the air conditioner compressor pulley, the power steering pump pulley, the water pump pulley and the idler pulley. Once the belt is routed inside each accessory pulley, inspect the belt to make sure that it is securely inside the pulleys.

Crank the 1999 Dodge Caravan for 10 to 15 seconds to completely seat the belt ribs in the grooves on each accessory pulley. Shut the engine off and close the hood.

If the belt routing diagram for the 1999 Dodge Caravan is missing, use a pen and a notepad to draw the exact routing of the old belt and use it when installing the new belt.

Here is a complete writeup from subaru on how to replace the timing belt oh a ej25 dohc.

http://endwrench.com/pdf/engine/FtTimingBeltReplaceF00.pdf

If you need any help along the way let me know I have done this timing belt a few times.

There is a belt tensioner on the front of the engine block that needs to be taken off and compressed(use a vise if possible) you can use a small allen key or something of similar size to lock piston intoethe compressed position . Then reinstall. I am assuming that the belt routing is correct but the compression of the tension cylinder needs to be done for proper belt tension.