Charging problems

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Apr 1, 2013 | 11:56 AM

minus40

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From: Whitehorse

Charging problems

02, 7.3 with dual alternators. New batteries. Vehicle is 200 km from me in Tuktoyaktuk! Driving up to Tuk yesterday (ice road), about 1/2 way the batt light came on. Eventually gauges died and engine stopped. Caught a ride back to Inuvik last night, but going back up to troubleshoot/repair/baby it home next day or two. I need some advice on how to check the alternators. No parts store to check alternators within 1500 KM. Remember, its still -25 or so and the truck is in a foot of snow, so I need realistic ideas to test it, or fix it, or baby it to Inuvik where a mechanic can overcharge me to look at it! Got a small list of things to look for from internet, but I expect its just bad alternators. But... don't want to buy 1 or 2 without being SURE they are bad. Pulling a batt cable off when it is running seems like not enough diagnostic before I start replacing alternators. (yes, I can charge the batt and it will restart) (Gonna baby it home with extra batts)

Apr 1, 2013 | 12:41 PM

Texas Chain Ring

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I had a charging issue I had checked out at Autozone just a few days ago. The only way I can see it for you to test in real world out in the Arctic Circle is to have the same battery/alternator/starter tester that the shops use. What they did was hook up to one battery with the truck off. Then they switched to amperage draw on the starter and alternator and had me start the truck. When any electrical motor is weak it over pulls in amps to make up for the windings being worn. If either alternator is bad it'll show on the tester by way of high amp draw as you try and start the truck, still connected to the battery.

but again, it's a special tester they use, an all in one.

Apr 1, 2013 | 12:50 PM

ggirten

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Joined: Mar 2003

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From: Western Kentucky

When my alternator went bad, the truck slowly shut itself down. First the dash lights and radio. Then the transmission started to shift odd and finally quit. Once it sat a while, the batteries recovered and it started enough to get home. When running, test the batteries with an Ohm meter. It should be putting out 13.5 to 14 volts. If lower, then probably bad alternator.

Apr 1, 2013 | 02:16 PM

howellt39

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From: Portland, OR

Easiest check is to take a multimeter set to DC Volts, put one lead on the batt negative terminal and one lead on the hot pole of the alternator while the engine is running. You should be getting in the neighborhood of 14.4V for each alternator.

If one is significantly lower than the other, that's the prime suspect.

Apr 1, 2013 | 06:17 PM

Mowing Man

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Joined: Mar 2012

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From: Quaker Hill

Thought my alternator went this winter, and replaced it-twice. Turned out, i had blown one of my mini fuses under the hood. I had a short between the main electrical box connector on the valve cover and my alternator. One of those two little wires on the top of the alt. provides electricity TO the alt which then allows it to produce the voltage to charge the batteries at 13.5-14v. I would change the fuse and it would go until I hit a good bump and short it out. Seems strange that both your alternators would go at the same time. Both those small wires in the alt. (green with a red stripe, orange with black stripe) should have 13.5 volts with engine running. If you don't, that's most likely your problem

Apr 2, 2013 | 09:03 PM

minus40

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From: Whitehorse

problem solved

Talked to a mechanic up here that works on 7.3's all day long. Long story short... I got the only alternator in town, and went to Tuk, put it on and it was charging right away. Chose to replace the top one! Now that it is in Inuvik, I will test, and almost for sure change the other one. Everything I read, hear and was told is that the dual alt set up is so over the top for a non ambulance setup, that when one goes you never know it unless you have a super power draw (ambulance etc). Then you drive around like every other vehicle on the road with one alt. And when it goes, just like everybody else, you know it. So thanks for the posts, advice and communication. They all helped in one way or another.