Electrical system woes

[Anonymous]

A few weeks ago while I was driving up near Vail on I-70, the truck started sputtering (the lights dimmed and engine power was greatly decreased) and the red battery light started flashing at me. I was going along at about 75 and going up hill, so the engine was working pretty hard. So I turned off my lights, radio, A/C, and radar detector and the battery light turned off.

Then again the other day, I was getting on the truck hard to get up a hill (I needed to get over because my lane was ending), so I turned off my A/C to free up some power and switced the control knob to allow outside air in. My lights dimmed and the red battery light flashed on, and again, engine power decreased. It stopped after a few flashes (I was simultaneously letting off the gas, maybe that's why it stopped), but this has me kind of worried.

I've never had a problem with the battery/electrical system before. Truck starts up fine and I had my 60,000 mile service not long ago, and supposedly everything's in working order.

Anyone have any idea what it could be?

[clavos]

I'd start with having the alternator tested. I think Checker or Auto Zone will do this for free while it is still in the vehicle.

[mattadams]

yeah my first hunch would be alternator too... since its the alternator that does the charging for the rest of the system, and might not be putting out enough output for what the vehicle needs... could be a good time for an alternator ugprade :). I've got a 150 amp alternator from wrangelrnw (wranglernw.com), they also make a 200 amp version.
Could also be some other problem with the leectrical system liek the battery not holding enough charge, but my hunch would be alternator.

[Tray]

Alternator
Battery
Alternator connections

If it weren't in that short list I'd be very surprised.

[Glass]

Make sure that if you are checking everything out anyways that all ground wires are properly grounded, the connectors are free of corosion, and that wires are in genrally good shape and free of anything that mgiht hit them

---JOHN

[Anonymous]

Thanks for the input everyone, I'll letcha know what's going on with it when I take it in next week. :)

Edit: How long do alternators last? I have the tow package so I think I have the 130amp.

[mattadams]

Depending on what kind of abuse you put the alternator through (extra accessories, towing, blasting a/c while runnign the engine full blast, etc.) the life span can vary. The alternator in my old explorer lasted about 100,000 miles... I replaced the alternator in my F-150 at 75,000 miles, even though it wasn't bad yet, I just wanted to upgrade.
I'd guess typically around 100,000-125,000 miles though.

[Walking Eagle]

Know on wood, but I have my original in my truck with 140,000 miles.

[Anonymous]

The truck has just over 60,000 miles... I bought it used right as it hit 50k last October.

The only thing I've ever towed with it was a small Uhaul trailer from Dallas to College Station, TX (about 200 miles). Who knows what the previous owner used it to tow, though.

It's done a fair bit of highway driving and I normally have A/C running, radar detector and the stock radio on.

I'm thinking I overwhelmed it that time up in Vail. We'd been driving for about 2 hours (coming from over by Grand Junction) up and down the mountains and we were chugging along at a good pace; A/C blasting, radar detector on, head/foglights and radio on when it started struggling.

But wouldn't that be atypical for a relatively young alternator? Especially a 130amp one?

How much do new alternators run for?

[mattadams]

yeah that does seem like an abnormally short lifespan... might want to bring it to checker or autozone, etc. most will do electrical checks for free.

[Glass]

Just another little tid bit of possibly accurate info here....I believe that if any of the dummy lights (check engine, ABS, battery etc.) come on any time other than start up, that your computer should record the error that caused the light to come on in a memory code, these codes are stay in the memory for a varied amount of time after they have gone off, from what i have read, usually 20-35 starts after that, then they should clear. I would recommend that if you know anyone who might be able to do a computer diagnostic on it, that you have it done. That syould help you determine the cause of your woes. If you dont know anyone who has a diagnostic computer, maybe I can set something up so that next time you are up this way (preferably on a weekend) , i can get one of the county mechanics to run a diag. with thier computer. Hope something I have said helps somehow.

---JOHN

[Carlyle]

I had the alternator go on my last vehicle in the exact same manner. It was a piece of crap from Germany that I thought would last forever, but that's another story all together... Everyone I've talked to now says just to replace and upgrade the alternator at 75,000. Yours just went sooner... I may have the problem licked this time though with dual alternators!