About a month ago my battery light started coming on, which then turned into losing all dash lights around 2k rpms. I checked all wire connections and took it to Autozone where the battery and alternator tested fine. After this the truck went about a week to a week and a half without anything happening again.

Then last night the battery light started flickering again and when it did all the dash, head and tail lights got brighters, then dimmed again when the battery light went off. Also starting last night when I turn the dome light on with the dimmer switch, it sounds like there is a clicking sound coming from the fuse panel on the passenger side.

I went to Autozone this morning to check my alternator and battery again, They both passed though my alternator is probably going bad since it was just under 13 volts running. But I don't understand how that will make the fusebox click, or all the lights get brighter when the battery light on the dash is on.

Can someone tell me what could be the problem(s) here?




---07 Ford Ranger 4x4 4.0 L XLT----

 

Seeing as how you live in cold country, with salted roads, it may be battery cable, or connection problems, like loose or corroded battery cable clamps or posts, or a faulty battery to engine ground connection, or an internal battery problem.
Include the out of sight battery cable wire strand connections to the battery cable post clamp & the terminal lug connections on the other end of both battery cables.

Those kinds of problems can cause some strange electrical things to happen.

I've had one case where the battery cables, lug & post clamp connectors looked just fine, but the B+ cable had a bad out of sight connection of the wire strands to the molded on battery cable clamp. An under load voltage drop test finally ran that puppy down. I found out years later that the vehicle mfgr had a recall on the B+ cable!!!!! lol

If the AZ guy knew what he was doing, used the tester correctly & did his load test properly, their tester should have caught that kind of voltage drop problem.

If your in doubt about their testing, you can double check the load test with your multimeter, by measuring battery voltage across the battery posts, then applying a heavy electrical load, like turning the headlights & blower motor on high speed & measuring the battery voltage across the posts again, then across the post clamps & lug connections to the engine ground point, the starter B+ connection & the B+ feed to the under hood power distribution fuse/relay box. If the under load battery voltage across the posts & cable connections are ok, suspect the alternator. Maybe worn brushes, leaky or open circuit diodes in the alternators regulator. The alternator should be putting out about 14.5 volts at about 2000 rpm, so the less than 13 volt reading is low.

If you don't have a multimeter to do the under load voltage drop test, another quick check & sign that the battery, cables & their connections are likely ok, is the engine cranking speed being ok & the headlights not dimming much when the engine is cranked.

So if the load tests seem ok, which suggests that the battery cables & connections are likely ok, I agree that the alternator is suspect, if it's putting out less than 13 volts.

More thoughts for consideration, let us know what you find.

 

When the battery light comes on while I'm running the engine, the Lights don't get dimmer they get brighter.

 

Sounds like an alternator voltage regulator problem, or maybe a ground problem, so what does your in dash volt meter show, or better yet, your multimeter say the voltage is, when the battery warning light is off, then what is the voltage reading when the battery warning light is on & the lights are brighter????

When the lights are brighter, it suggests the voltage is higher & if it's high enough to turn the battery warning light on, it suggests the alternators voltage regulator has a problem & the voltage is likely high enough to do damage to voltage sensitive things, so you need to get this problem put right without delay & putting it right means the alternator voltage regular needs changing out, or if you can't do that, or don't have a repair or rebuild shop that can do it, you need a another alternator.