I have a 91 Olds Ninety Eight. Neither low beam light comes on. The hi's work fine, as well as all signals/parking lights etc. In trying to figure this out, I replaced the dimmer switch which is mounted on the steering column (no easy task) which made no difference.
Then I removed the bulbs and connected them directly to the battery, and they light up, so I think they are OK. Then with the low beam bulbs out, and a voltmeter connected to either side plug, I get 11.6 volts at each plug with the dash headlight switch on, and it shows zero when I turn the switch off, so I think the switch is good as I'm getting juice to the plugs, but when I put the bulbs back in, nothing! I'm assuming the two wires connected to the lamp sockets are pos and neg, is this true? I also assume that 11.5 volts would be enough to light the bulbs, as the battery shows 12.5 volts and the bulbs light up when jumpered to the battery directly, right? Any ideas appreciated.