Got the indication fault on the dash, that my right rear turn signal was bad. Bought the new bulb, and replaced it. Buttoned it all up, but still getting the dash fault, and the right side signal is still in “ fast mode”. But, the turn signal is flashing OK.

So, how do I get the fault to permanently go away? This began about the same time that I replac3d the battery, with a dealer purchased Jaguar branded battery.

 

That's a bit weird - you could try disconnecting the battery to do a hard reset - make sure the battery is fully charged before reconnecting

 

Thanks McJag,
That is my next move, as I am perplexed at this point.
I also plan to remove the TL assembly, and examine the wiring, very closely.

 

I had the self same problem. The replacement bulb I fitted was a known brand from Halfords.

The solution was to buy a much more expensive, "factory" original bulb from SNG Barratt.

Apparently, the resistance (or impedance?) of the bulb must be within a certain range in order not to register as a failed bulb.

 

Thank you! This makes sense, as I picked up a bulb from an auto store, that had both the same part number. I will get a new one from SNG Barratt.

 

Since I happened to be going past my local JLR dealer, I decided to just get the bulb from them.
Hole Catsh#&#$t Batman, $23. Dollars and change for one bulb!
if it fixes the issue, I will be OK with that though, won’t know until I get back from travels.

 

This all seems very odd to me. The resistance of an incandescent light bulb is related to its wattage (i.e. brightness). If two 12V bulbs have the same wattage they should have very similar resistances.

 

@justinhill , you're entirely right of course. However, who's to say the replacement bulb was in fact a classic incandescent bulb.
As you know, wattage does not necessarily imply brightness. "Lumens" does. (providing for clarification of others)
There is no need for a Jaguar branded bulb. But a correct bulb type is essential.

Cheers!

 

Maybe it is odd, but the issue only arose after the non OEM bulb was used.
As I said, if it corrects the problem, all good.

 

My understanding is that the bulb must have a resistance (or an impedance perhaps, which is not the same thing) within a fairly tight range or it is flagged as having blown. e.g. (invented numbers, not measured) perhaps a resistance between 1550-1650 ohms. So if it is actually 1750 ohms it wont be significantly different light output, but will get flagged as a blown bulb. Of course it doesn't have to say JAGUAR on it, but you cant take an test meter into Halfords and go through all the bulbs until you find one within the range limits, because you don't know what they are, and Halfords might object. So the only way to be sure is to buy a Jaguar approved one.

 

It's elementary my Dear Wattson - W = I squared x R

 

Factually correct though kind of misleading in this, fixed-voltage, situation since it sort of implies that increasing resistance would increase power, rather than the opposite,

W = I x V - power is amps x volts. I = V / R - amps is volts divided by resistance. Where V is fixed, increasing R reduces I, and W.

 

one tip if I may, replace them in PAIRS

 

is that because they usually fail about the same time, or, another reason for your comment?

 

as a mechanic we were always taught to do so..in practice I've seen the other fail immediately...different resistance maybe but too many times to be a fluke...and on resistance the jags are pissy