No low beam headlights

The high beam indicator stays on and when you turn the vehicle off the headlights take a long time to dim out.

During the night time driving, I have lost my headlights. Usually when this happens, the bright head lamps still work, but not always. This has happened about 6 times. When I took it for an inspection, it failed. The technician would not pass inspection on it and told me it was the dimmer switch. Since then, I have had it in the shop with 2 different GMC certified dealerships and they say that until it does what it does while they have the car in the shop, they cannot order a part until they witness what is happening. What is this, the dimmer switch or a short? The problem always goes away and the lights eventually come back on, but this has to be fixed as it is dangerous! Any suggestions as to what to tell the mechanic as the Envoy is currently back in the shop. Still waiting for the problem to act up while they have it in their possesion!

I have a 2003 GMC Envoy and the right headlight burned out. When I replaced the bulb it only worked infrequently ( I used replacement bulb 9006). Upon closer examination I noticed the clip on the bulb was brown/black. Could the wrong bulb cause this? Could the clip burn out over time? Can I replace the clip only or do I have to replace the whole headlight assembly?

When I wiggled one of the wires on the connecter it would cause the light to go on or off. The headlight had remained on until this happened.