1157 Bulbs burnt out

Question

My back up light on the driver side burnt out on our last trip. Then when moving the motor home here at the house I noticed the brake/turn signal bulb was out now too.
Removed both covers to find cloudy bulbs. White coating inside the bulbs, guess this just means they just burnt out.
Question is why did manufacture use the same bulb in both sockets? 1157 is a two element bulb and I cannot figure why it would have been used for the back up light? More light if both elements were lit?
Any thoughts?
Thinking about going to led's as I recently put them on my dolly and love the bright light that they put out.

msmith1199 · Answer

Using the same bulbs may just be more efficient.

ed6713 · Answer

As you said, LED's are the way to go. Do it once and forget it.

dutchmensport · Answer

1157 is the two element bulb. 1156 is the single element bulb. The side pins on both bulbs are positioned different so you have to use the correct bulb to fit the socket. RV manufacturer probably got a boat load of lights with the 1157 configuration, but the design of the trailer called for a single element bulb. So the manufacturer ran only the single wire to one element, even though the socket had wires for 2 elements.  Had both elements been wired into 1 wire, I don't think it would have been much brighter anyway.

fire_up · Answer

helperzack wrote:My back up light on the driver side burnt out on our last trip. Then when moving the motor home here at the house I noticed the brake/turn signal bulb was out now too.  Removed both covers to find cloudy bulbs. White coating inside the bulbs, guess this just means they just burnt out. Question is why did manufacture use the same bulb in both sockets? 1157 is a two element bulb and I cannot figure why it would have been used for the back up light? More light if both elements were lit? Any thoughts?Thinking about going to led's as I recently put them on my dolly and love the bright light that they put out.helperzack, As has been stated, it's merely a cost/more efficient approach to streamlining the manufacturing/assembly process. Our '04 Itasca Horizon, 36GD with the C-7 330HP CAT, is setup the exact same way in the tail light assemblies. It's utilizing the same bulb, in six sockets back there. One on each side is purely running. One on each side is running and brake. And finally, the bottom is backup, on each side and, yep, using the same bulbs. Sure makes it easy to keep a spare bulb on hand. The old adage, "ONE SIZE FITS ALL". Scott

scottg · Answer

The white residue is indicative of an air leak while the bulb was illuminated.

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1157 Bulbs burnt out

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