4.2 ignition switch

Was getting some “ignition sputter” and when I giggled the ign switch it stopped. took the switch apart and found the contacts are badly worn. Anyone know of a way to build these up or a source for these internal parts?

They are on Ebait all the time and pretty cheap. I’m sure the ‘usuals’ carry them also. Not really worth the time to repair when new units are readily available.

Tom , I repaired mine it didn’t last long. I found this place and replaced the switch now there is no problem.

I had this problem. It was caused by having too many keys on the ring with the ignition key. The weight pulls the internals off a tiny bit nd after a while the internal contacts spark and burn creating shorts and stopages.

I did not take it apart, but I did bang the contact together EXternally. In the end I replaced the ignition switch.

Don’t carry so many keys on the XKE ignition switch ring.

Consider installing an ignition relay so the ignition switch only runs the current to the relay coil. This takes all current out of the switch.

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My 69 E Type had difficult to find and fix ignition problems usually happening at intersections or motorway on-ramps. I renewed all the usual suspects but to no avail. Finally replaced the ignition switch, threw away the new ignition leads and new Champion plug caps and used carbon trace leads - - now all OK

Hi Alan and welcome.

Can you describe the problems/symptoms. It might help someone else with a similar problem find a solution.

Happy to reply, I thought that my problems were heat-related as they usually appeared after about 20 to 30 minutes of running and resulted in uneven running and often complete cut-outs - most often at intersections or light sequenced motorway on-ramps. Sometimes the engine would stutter when accelerating in third or top gear. On initial start-up the car would usually fire at first touch of the starter and idle cleanly but not so good when hot.

Not so for the 5 spade 4.2 switches. None on ep-bay. And—it is easy to disassembly the switch---------points and contacts can get dirty and need cleaning on my case, the contacts had a depression on them such that the points were not making good contact. I bent the points outward some and hope this will solve the problem.

I’ve had some luck adding a blob of silver solder to worn contacts and filing it back to shape. I had to do that with the wiper park contact since it was unobtanium…

Hi Tom, I chuckled at the thought of you " giggling " at your switch…If you had jiggled it I could understand !! Ericas suggestion of using silver solder is good…regular solder would be too soft. To replace the spring would help. Also as has been mentioned … by far the current through the switch is too high .the best defense is to insert relays in some circuits, especially the ignition because that is a high load item.The used oe switch in 1970s Jags ( eg XJ6 ) are worth considering.

Hey. I like my giggling switch;):). I took it apart cleaned the contacts and bent the contacts up a nit to make sure tjey make form contact. It is working. For now

I can look at my spare Rovers: I think their switches are 5-lug.

Let me know if I can help.

Does your Jag do this, going down the road?



that would be great Paul. I’d like to have a solid one (not worn down) one to install.


thanks Erica------might try that. Hope all is well with you


I’ll check today: These haven’t been used in at LEAST 20 years, so are likely fairly robust and minimally worn.

Who knows? In all the parts boxes, INSIDE a couple of the cars, I may have a new one!

Yes, just amazing once again how stupid those Jaguar engineers were. Many of theses ignition switches are only lasting 30, 40, 50 years. Pure junk! :grinning: :grinning: :grinning:


fantastic!! hope you can find one. please let me know



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