84 xj12
when refitting the rev counter and speedo I noticed the speedo has 286 2.2w capless miniature wedge
bulbs in the indicator warning light and the rev counter ind warning light has 501 5w capless wedge bulbs, are the 286 bulb used on the speedo for a reason? jaguars list 5w in their parts list but only show 1 in the illustration, I have ordered
led 501 bulbs and 286 led in various colours, but how do you get equal brightness with different size bulbs
http://www.jaguarclassicparts.com/uk...warning-lights

 

Often lower wattage bulbs were used keep heat down so the plastic or color filters close to the bulb don't melt. Lower wattage bulbs also tend to last longer. This may be a change done on the assembly line or at the dealership after the manual was printed.


I've never found LED bulbs to work properly for a few reasons in the Jaguar gauges. The color was off and the directional nature of LED bulbs tends to make the gauges not illuminate properly. LED bulb technology is evolving so it perhaps you will have a better experience.

 

I have read that some people complain of the Jag's gauges fogging up when LCD's are used to replace the original bulbs. They dont get hot enough to dry out humidity...

 

the reason for the bulb differential (as icsamerica so rightly says) is heat
the small bulbs in the speedo are 1.2w but are magnified so the rev counter has to have a 5w to keep the brightness the same, I am going to try various matching colour led's in there if there is enough depth, I don't think the top illumination light in the rev counter will take an led without spacing the holder away 1/4" from the case as the green is a bit close, unless someone can help on that matter,

 

"I have read that some people complain of the Jag's gauges fogging up when LCD's are used to replace the original bulbs. They dont get hot enough to dry out humidity..."

That's a good point. I know on humid days my fuel/temp/volt/oil gauges are really bad for fogging up when the headlights are on. Even when they have been on for 30 minutes they are still a little hard to read. I had to replace all the bulbs. And only 2.2w was available on order. $3NZD each !!! I got told they are not common enough to bother keeping a regular stock.

 

my 1984 XJ-6 is the same way, at some point I thought someone had replaced the harness but with a newer model year but no, it's factory, different bulbs and different sockets for the Tach and Speedo. Very weird.