Re: Intermittent power drop when headlights are turned on

Posted by HH56 On 2012/2/3 15:46:09

I'd do a couple of things. First would be verify generator belt is proper size for the pulley, tensioned properly and not glazed or slick. Increased current draw puts a load on the generator and if something is slipping, generator maybe not turning fast enough to keep up with demand. Since it doesn't seem to return to normal with items turned off, probably not the reason but worth checking anyway. Another thing worth checking is make sure the ground wire between generator and fender tie point and then on to regulator is in place and good connections.

Since the lights do not dim, or turning things off doesn't help, would verify proper operation of the ammeter. It could be dirty or have a piece of lint inside and when deflected on initial surge maybe not returning to proper spot reliably. This could be done by installing a second inexpensive aftermarket ammeter in series with the original so you can compare the readings. This can be a temporary thing although several have installed and hidden one just for the verification purpose. If the second meter differs considerably then look to the original and if they match, then time for an electrical shop with proper diagnostic tools. Even though things replaced, you still could have an intermittent bad generator or regulator or connection.

If belt is OK and you'd rather not mess with ammeter, then you could just take the car to a shop and have a load test done. Many places do them for low or even no cost if you buy another service. They have monitoring equipment that could verify with all the accessories on, generator is putting out the proper 7.4 volts and 35-40 amps. You could have them turn on all accessory combinations you normally use one at a time and if any is pulling excess it should show up right away.