Both headlamps blew at the same time ?

67Dart273 said
You probably have voltage drop in the ignition harness. With key in "run" but with engine off, find your 12V switched ignition. Leave one probe on that connection, put the other probe on the battery positive post. If you read more than .3V (three tenths of one volt) you have drop in the harness. This drop ADDS to the VR setpoint.15V is not enough to blow up headlights. It IS enough to boil a battery.
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Ok, where would you recommend tapping in to the 12V ignition source. under the dash or under hood ? not sure if it matters or there is a preferred component, ie ignition switch to get the reading. obviously the easiest access would be easier !