If the tester doesn t light, then the earth is at fault. You can often correct this by cleaning the earth. Check your manual to see at what point the earth fits to the vehicle. Unbolt the connection and clean the tag connector and the body work with emery cloth. Now apply some Vaseline to this area.
Tungsten bulbs are cheaper than quartz-halogen and they last longer.
The advantage of the quartz-halogen light, however, is that it emits a brighter white light and will not dim with age. If you do go for a quartz-halogen bulb, be sure not to touch the glass portion of it. The oil in your skin will attack the surface and will cause a hot spot that will cause the bulb to quickly blow out. Inc. PageWise makes no representations about the content published on this site. PageWise hereby disclaims all warranties and conditions with regard to this information, and user agrees that all such use is at its own risk.