So I bought LED replacement bulbs to try and improve the light output on my reverse lights and the globe wouldn't fit. Are they supposed to have a single post globe or twin? Trying to work out if mine has been altered and I need to find a new holder that takes a single post globe. One side the globe went in and the other it would not. Just no use me heading to the wreckers and finding out the wrong one is the side that takes a single post as a replacement holder will not actually help.
The bulbs with 2 solder pins on bottom are only for brake lights and park lights (combined in one bulb) so these are basically 2 bulbs in one.. one of the bottom pins connects to the thicker fillament inside which is the 21W brake light and the other bottom pin connects to the thinner fillament inside which is the 5W park light. The reason why the small side pins on the metal cyliner part of the body of the bulb are offset (one higher, the other lower) is so that the bulb can only be fitten in place one way, so that the brake light comes on when you brake and the park light comes on when you turn lights on, and not the other way around. The bulb holder that you say is for your reverse light, which has the offset pins and 2 contacts on bottom would actually be for the brake/park light, not for the reverse light. So it's possible that you may have the reverse light bulb holder in the wrong place on the back of the light. The bulbs and bulb holders with single solder contact (on base of bulb) and only one contact at base of the actual holder are always for either indicator OR reverse ligh, both are identical 21W bulbs.. these also do not have the small side pins offset, as it is irrelevant which way they go into the bulb holder.