For several years I have had four HD units - all on the same circuit. Within a few months, two of them went out. So I ordered two of these lamps, installed them and - nothing. So don't think the bulbs are bad. The lamps were to blame, although there were no signs of internal damage. They even had a normal "hum" when turned on. New replacement bulbs worked fine in other lights. Too bad I didn't take the time to look at them beforehand. But I'll keep the old bulbs as spares and put the new ones (they're a bit brighter when they're new) in the work lights. I then converted the faulty lights to LEDs by removing the ballasts and plugging the outlet directly into the line-in. With the new 15W/5000K LED lamps, they are just as bright as ever. So if you have another working headlight, test your "bad" bulbs in it before purchasing a replacement. In any case, a good reason to convert the lamp to LED and save even more energy. They fit the same socket as HD incandescent bulbs - just remove the ballast and plug straight in.
CHANZON 100Pcs (10 Colors X 10Pcs) 3Mm LED Diode Lights Assortment (Clear Transparent Lens) Emitting Lighting Bulb Lamp Assorted Kit Variety Colour Warm White Red Yellow Green Blue Orange UV Pink
41 Review
PHILIPS 901573 Master Color Elite
8 Review
E12 Led Bulb Dimmable 4W 5000K Daylight, Type B Light Bulb Golspark 60W Equivalent, E12 Small Base Candelabra Led Light Bulbs, B11 Chandelier Candle Light Bulbs For Fan Light, Flame Tip, 550LM, 6 Pack
20 Review
π‘ GoodBulb LU70/MED - 70W E26 High Pressure Sodium HID Bulb, 2000K Warm White - 2 Pack
7 Review
Bulbrite A19 Solana WiFi Connected LED Alexa Smart Light Bulb, Single-A19, Tunable 2200K-6500K Color Temperature, Frost Finish
28 Review
Lamp LED Ergolux 13638, E27, A60, 15 W, 4500 K
12 Review
Illuminate Your Space In Style With I-SHUNFA'S Stained Glass LED Light Bulbs - Perfect For Home, Parties, And Festive Occasions
14 Review
Set Of 4 Geeni Prisma Wi-Fi Multicolor LED Light Bulbs, 1050 Lumens, 2700K, Dimmable, No Hub Required, Compatible With Alexa And Google Assistant, 75-Watt Equivalent
41 Review