I just replaced battery and alternator on my 1999 ford f150, still wont turn over, need advise

The simplest way to see if the charging system is OK, is to turn the truck off. Check the voltage at the battery with a volt meter. It should be around 12-12.5Vdc. Start up the truck, the voltage should be 1-1.5V higher. Alternator is "probably" OK.
If in doubt, remove the alternator and take it to AutoZone, and have it checked.

recharge the battery and once stated disconnect the neg cable, if it dies the alternator is bad,

There are few possible reasons why battery is not holding charge.May be its weak battery or there is loose connection between battery to alternator.There are few troubleshooting help links,related directly to these types of problem,with there troubleshooting procedure.--------Click the link below and go through its troubleshooting details to resolve the issue:---Car battery loosing its charge overnight? http://schematicsdiagram.blogspot.com/2011/11/car-battery-loosing-its-charge.html
--------How to troubleshoot car battery?

http://schematicsdiagram.blogspot.com/2011/06/how-to-troubleshoot-car-battery.html

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After replacing Alternator, the battery indicator light Comes ON dash? http://howtobyme.blogspot.com/2011/11/after-replacing-alternatorthe-battery.html
----------1998 Ford F150 pickup Battery Drains overnight due to Alternator? Alternator drains car battery? http://technoanswers.blogspot.in/2012/02/1998-ford-f150-pickup-battery-drains.html---------- 2002 Ford Focus sits over night and battery goes dead? http://technoanswers.blogspot.in/2012/02/2002-ford-focus-sits-over-night-and.html----------- Charging system problem on Chrysler LHS car? http://technoanswers.blogspot.in/2012/02/charging-system-problem-on-chrysler-lhs.html
-----------Toyota Corolla: Battery Drains out? http://howtobyme.blogspot.in/2012/05/toyota-corolla-battery-drains-out.html--------- 1999 Ford Taurus: Battery not holding Charge? http://whoisbyme.blogspot.in/2012/06/1999-ford-taurus-battery-not-holding.html
-------------How to Inspect Car battery? http://repairhelpcenter.blogspot.com/2011/12/how-to-inspect-car-battery.html------------ How to Test Car Battery? http://repairhelpcenter.blogspot.com/2011/12/how-to-test-car-battery.html--------- Car Battery Servicing? http://repairhelpcenter.blogspot.com/2011/12/car-battery-servicing.html--------- How to Replace Car Battery? http://repairhelpcenter.blogspot.com/2011/12/how-to-replace-car-battery.html-------- How to Inspect Car battery Terminals? http://repairhelpcenter.blogspot.com/2011/12/how-to-inspect-car-battery-terminals.html---------- How to clean car Battery terminals? http://repairhelpcenter.blogspot.com/2011/12/how-to-clean-car-battery-terminals.html---------- How to Replace Broken Car Battery Cables? http://repairhelpcenter.blogspot.com/2011/12/how-to-replace-broken-car-battery.html
--------------These details and procedure will help.keep updated for more help.Thanks.

try removing earth cleaning it and replacing it again.....maybe lol

Is it really not charging, or is your battery not taking a charge?

Are your battery terminals clean and tight?

Have you had a load test done on the battery? A failing battery won't hold a charge (this is not to be confused with a alternator not charging)

Sounds like the voltage regulator inside the alternator is going bad. Make sure all the connections to the alternator are clean and tight. Disconnect the battery, disconnect the alternator connections one at a time, inspect, clean, and reconnect each one. If you still have a problem after this, take the alternator off take it to someplace like AutoZOne, and they'll check it for free on a special test stand.

check & clean the battery terminals first. Also, clean any small wires coming off the positive post.

Go back to your battery connections and make sure they are clean. If you recently replaced terminal ends, pull on the wires and see if it cranks.

get the charging system check before you stall with it normally the alternator is not charging hope it help fixya our post thanks pierre

the basic amperage of all vehicles is 14 now if your using a higher output alternator you will want to go with a 16 or 18 amp alternator but overall you can order the alternator straight from dealer or any parts stores
i dont recommend junk yard for these kind of parts you really dont know what your going to get