its due to space and heat a resister wasn't used on this bulb, the bulb is a small dash bulb, life span of this is well, as long as the car I hope as I have not seen any dash lights go on a car, even of 20 year old ones so fingers crossed, its the weakest link but easy to change as it just pops out.
When I designed this the technician at the factory wanted to put resisters as he was confused on my designed but I drilled it into his head I am paying for the mould so he needed to make it how I made the drawings.
I will leave pictures to Neil as he has a good camera

Any other questions then please ask.
trups