I'm pretty low tech on stuff electrical, but how can one check with a volt/ohm meter these old T3 headlight bulbs to determime if the bulb is good or bad? The three tabs on the rear are low beam, high beam and ground. What resistance readings should I see for a good bulb? They seem dim, however it may be something else besides other than the bulb. Just trying to eliminate the bulb as the problem. Any suggestions?