Ok so, I start my truck up and it runs idles and drives fine, but it seems to be when I turn the headlights on it will start to bog out and lose power as you try to accelerate. Doesn't do it everytime. I've traced all the wires I could and can't find any bad grounds or corroded ones. So I'm starting to think the alternator is screwing up some how, but it keeps the battery charged. So from there I'm lost idk what could be messing with it bad enough to run fine with everything on but the headlights, but as soon as there on its starts running rough.
My car has 180000 miles.
My car has an automatic transmission.
The battery should be load tested and the output of the charging system should be measured. If the battery passes a load test be sure it is not a marginal pass in which case you should definitely install a new battery to reduce diagnostic headaches. Batteries are a very important component in a car’s electrical system. If this symptom you are having with the poor acceleration is truly tied to operation of the headlight circuit, the current draw of that circuit, as well as the ignition circuit, should be measured with an ammeter to determine if there is some sort of electrical problem. If it turns out that the battery is good, the charging system output is within Factory Service Manual specifications, there is no abnormal current draw on the headlight circuit (or voltage drop on the ignition circuit), your best option is to request a failure to accelerate diagnostic and the responding certified mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
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