I have a 1998 xk8 x100, I have 3 key fobs with fresh batteries and cleaned contacts. Two of them were working perfectly until now. I have re-programmed them 3 different times, both responded by lighting up red light on console, when I get out of car and test them they work on the first try, then after a minute or so they stop working, sometimes one will work later in the day, anyone have an idea what might be causing this problem?

Jack M

 

I assume your fobs are the older style which take two batteries (see Motorcarman's photo below)?



If you have the correct batteries, I would take the fob apart and clean all the contacts again and see if anything improves. If not next stage is the receiver in the boot.

There is a recent thread on here you should have a look at.

https://www.jaguarforums.com/forum/x...t-open-290612/

 

Thanks for your response, I have cleaned all contacts, the rubber contacts and have fresh batteries (2), the fobs were working until recently when they started working intermittently, the car is a convertible, do you know where the transmitter is located?

Jack M

 

I have a dozen old fob from years of collecting. Most of them have at least one button that failed or intermittent.

I bought a small jar of conductive paste and applied it to all the rubber pads on all the remotes I have.

All are working reliably now even though some have no markings left on the outside. Just black rubber buttons.

 

If only one or two of the buttons don't work you need to dismantle the button membrane and clean it with contact cleaner or alcohol.

If none of the buttons work and the two batteries are good, it is more likely to be a slightly misaligned contact arm. The early fobs are a terrible design and a slight sag or misalignment of the little arm causes it to fail to make proper contact with the small square PCB copper pad on the opposite side of the fob. I have this issue every 5 to 10 years and careful bending/straightening of the little arm is required. It would be easy too snap off the arm so great care is obviously needed.

Richard

 

Cleaning is the first step but the conductive layer will eventually wear off and needs to be renewed.

 

Thanks, I did encounter that little are and figured out where it should contact the circuit board..

Jack M

 

Thanks for the advice, just for clarification, is the conductive paste you refer to also known as dielectric grease?

Jack M

 

It is the OPPOSITE of dielectric grease. It is conductive.

 

you can get the proper conductive grease on Amazon. The best one is silver based. A small tube is $50 more or less, it you use only a tiny bit for each application. I’ve had my tube for years and it still looks full.

https://a.co/d/h6OOS2h


The copper based grease is much cheaper, but I’d use the silver if you can afford to sink $50 in a small tube that will last you a couple of decades.

it’s amazing how many people will argue that point. There a lot of bad info on the internet regarding its use, some falsehoods even on the product packaging !

if one would only look up the definition of “dielectric” that should be enough to teach something.

I use dielectric grease sparingly on rubber light boots or spark plug boots to keep out moisture. But never directly on electrical contacts.

Z

PS the grease I use was $35 when I last checked on the availability a couple of moth’s ago I . Tariffs have had an impact already