92 crown vic electrical problems

My son has been driving my vic to work for awhile. He works nights so this happened at night. Coming home from work the batt light comes on and then the car dies a few miles later. To get him home we bought a battery a Wal Mart. We change the alternator the next night. He drives to work the next night and the belt broke a couple of miles from home. We put a new belt on the next day while he was driving around Sunday night and the battery light comes and dies. I go up and jump start him and it ran fine and the light went out. The next day the battery light is on again and we go up to have it tested. The batt light is on all the way there. I had to jump start the car to get it started. when I jump start the car batt light goes out. I put a trickle charger on the battery all night. I start the car up and the batt light stays on. It seems when I jump start the car everything is ok. Otherwise the batt light stays on. When we had it checked they said alt. was ok and the battery was a little low, I checked with a old volt meter and as near as I can tell battery is still low. If meter is right about 10 volts. Help any ideas.

Is the voltage regulator built in to your Alternator or is it on the firewall? I had this issue on my old 86 Dodge 150 truck and the issue was a bad voltage regulator. I know older Ford vehicles did not have the regulator built into the alternator. I just don't know on your 92 Vic if that is the case. Just sounds a lot like that is the issue to me.

I will have to check but I think it is built in. Will get back Thanks

It is build in, I ran some other test that I found on the interweb, I think its either in in a fusible link or something simple that I'm missing

check all your connections and wires between the battery and the alternator and clean any corrosion. also if you have a volt meter with ohms and check the resistance between the post on the alternator and the positive terminal of your battery

I have a similar problem with my 93 Crown Vic. Battery/alternator warning light comes on. Fuse number 15 (under instrument panel) blows. At times testing at the battery gives 13.8 to 14.5 volts, alternator charging battery. At other times there is only 12 volts, alternator not charging battery. The 30 amp alternator fuse in the engine compartment power distribution box never blows. Replace the 10 amp number 15 fuse (instrument cluster(battery warning light) and abs circuit) and the alternator starts charging again. I have removed the fuses to the abs brakes. My next step is to disconnect the instrument cluster connector. I will not see the battery warning light but will connect a volt meter to keep an eye on the alternator. Trying to determine if the problem is in the instrument cluster. Both alternator and battery have been replaced.