while driving noticed battery light on, watched voltage meter dropping, lights were dimming, then went black. Truck was dead. Hood light came on when I lifted the hood and emergency flashers worked. 1st try to jump failed. 2nd jump worked. Left truck running (without lights) but didn't rev engine. When I returned, truck was dead and wouldn't start. Also, the underhood light no longer lights. Right now it is truly "Found On Road Dead". 1992 F150 Sound like battery, connections, alternator, or what? Thanks for any help.

Really sounds like it's not charging the battery. Missing ALT belt might cause such in an instant. If that's the case, you might loose the water pump, power steering, etc just as fast. Loss of water pump can cause further engine damage, so procede cautiously. I'd do a visual inspection while your have the battery charging with a battery charger. Then, if you have a volt meter, hold it on the battery posts of the battery. (Not the cable clamps.) Note voltage. If battery is good and charged, you will probably see 12-12.5 volts. Then have someone start the engine. (or do yourself) Then check the voltage on the posts again. I would expect to see 13.5-14.5 volts if it is charging the battery at all.

Guess this is just a start, please get back on what was found or tried and did or din't work.

Addie
c150l gave you good info.I might add,if you haven't cleaned cables,remove from bat posts use terminal brush.Charge battery With charger,and have checked.Even if cables appear clean,remove and clean.
Report back

AAA came out and "charged" battery. they moved the charger terminals around and after numerous tries it started BUT the battery light never went out and when the charger terminal was removed the truck died. The battery cables were not tight but the AAA guy said that didn't matter. Said the alternator was not working. Can you tell that by looking at it? Does this sound right? How much should replacing an alternator cost? Thanks.

i posted a reply but maybe i posted the wrong way. if so, sorry see reply above.

I disagree with service truck driver.
Remove cables CLEAN inside and out with terminal brush{cheap]also clean battery posts.Charge battery and have checked.You must have clean and tight connections.
Hope the alternator isn't cooked.Not
a good idea to jump and let alternator build it up.
Alternators are expensive.

thanks fordtracman. i'll follow your advice & i'll post results.

FINALLY followed your advice. battery was dead as a doornail--no hope for it, replaced. but light still on! new alternator--light still on!! I asked if a fuse link could be problem (at Advanced Auto) they didn't know if it existed in my model. purchased hayne's manual. found there is one. Low and behold, it had melted. i spliced/replaced link. Voila! light out, battery recharges, alternator happy, and me happy. although i didn't need a new alternator, my son and I installed it, our first. so it was worth the experience for both of us. fun and learned alot. thanks so much for your help. you were THE most helpful of all auto experts. thanks again. Addie

Congratulations. Know what you mean about quality time with your son being worth it.

Well, this turned out to be a very happy ending. I'm glad you got your truck up and running.