I appear to have a faulty switch. With ignition on, tweeking the terminations on the switch causes it effectively to turn the ignition off/on. When driving on Sunday, this ignition interruption happened a couple of times and was alarming. Testing in the garage illustrates the problem without moving the car.
My problem now is how to correct it. Can I get a new switch? I don't see any on SNGB site. More importantly, if I can get one, how the devil do I get the existing switch out/off the column. I have searched the manual and on here but cannot find anything definitive/pictures of what to remove.
Looking at my switch/lock with light and mirror, I think there is one sheer bolt sheered off and on top looks like a slotted screw, both in recessed holes. I have read on here that it is possible to remove the switch from the lock part but cannot see how.
Advices appreciated. TIA.
Replace Faulty Ignition switch?
#1 Replace Faulty Ignition switch?
Jerome Lunt
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT
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2008 MX-5 NC PRHT
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#2 Re: Replace Faulty Ignition switch?
Jerry, you don’t need to take the ignition key/steering column lock off. There is an electrical ignition switch at the back that can be removed and replaced. That way no concern with the sheer bolt. Look for the rubber boot on the electric gubbins at the back, slide boot out of way then look at the screws holding that in.
Report back when you’re ready to progress.
You’re looking for part no C35846, nla but if you search on here there have been other comments about finding them on fleabay looking for “Lucas ignition switch” or similar
Geoff
Report back when you’re ready to progress.
You’re looking for part no C35846, nla but if you search on here there have been other comments about finding them on fleabay looking for “Lucas ignition switch” or similar
Geoff
S2 FHC Light Blue
S2 OTS LHD - RHD full restoration
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#3 Re: Replace Faulty Ignition switch?
Hi Geoff. Thanks for that. I have now found that reference to the Lucas switch for Landie/MG etc.
My problem now is getting the old switch out. I've been told there may be a phillips screw to take out but I can see nothing on mine. I don't have the rubber boot getting in the way. I've also been told it may just be a push fit but I can't shift it ?? Maybe I need to be more persistent or use the Birmingham screwdriver too
I pulled the white wire from the switch and its clearly been getting hot, the sleeve is burnt. Perhaps I need to do the relay upgrade.
EDIT: It's out with the help of the 2lb "screwdriver"
That is, it were just a tight(ish) push fit, no screw fixing.
My problem now is getting the old switch out. I've been told there may be a phillips screw to take out but I can see nothing on mine. I don't have the rubber boot getting in the way. I've also been told it may just be a push fit but I can't shift it ?? Maybe I need to be more persistent or use the Birmingham screwdriver too
I pulled the white wire from the switch and its clearly been getting hot, the sleeve is burnt. Perhaps I need to do the relay upgrade.
EDIT: It's out with the help of the 2lb "screwdriver"
That is, it were just a tight(ish) push fit, no screw fixing.
Last edited by JerryL770 on Tue Apr 23, 2024 4:08 pm, edited 1 time in total.
Jerome Lunt
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT
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#4 Re: Replace Faulty Ignition switch?
This looks like the right switch to replace it by:
https://www.ebay.co.uk/itm/222338830301
Beyond me why SNGB can't list these.
https://www.ebay.co.uk/itm/222338830301
Beyond me why SNGB can't list these.
Jerome Lunt
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT
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2008 MX-5 NC PRHT
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#5 Re: Replace Faulty Ignition switch?
Jerry, not all are push fit and you’ll see a screw hole in that fleabay item to help hold it in place. Worth adding that. And yes, as Mich says in your other topic, upgrade to relay.
Geoff
Geoff
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#6 Re: Replace Faulty Ignition switch?
Got my switch and relay today and connecting it to my cabling, the switch works fine. However, it's a tight fit in the housing and where there is a lug on the old one to line it with a slot in the lock housing, there is no lug on the new switch.
As Geoff said, there is a very small threaded hole in the switch but of course no corresponding hole in the housing. Will be fun to get it in the right place.
I'm going to have to just fit the switch initially as I'm short of sufficiently large piggy back 6mm spade connectors for the relay wiring and I'm booked in for service Monday.
As Geoff said, there is a very small threaded hole in the switch but of course no corresponding hole in the housing. Will be fun to get it in the right place.
I'm going to have to just fit the switch initially as I'm short of sufficiently large piggy back 6mm spade connectors for the relay wiring and I'm booked in for service Monday.
Jerome Lunt
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT
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2008 MX-5 NC PRHT
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#7 Re: Replace Faulty Ignition switch?
Jerry, are you happy it can’t rotate in the housing when you turn the key?
Geoff
Geoff
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#8 Re: Replace Faulty Ignition switch?
I solved the problem of no lug on the new switch by cutting a small piece of ally sheet (lug size!) and super gluing it to the switch in the obvious position which mirrored my old switch. After 12+ hours to cure, the glue proved sufficiently strong to allow me to file it to a better thickness.
When it came to fitting into the lock body it was a b****dy tight fit. I actually tried to reduce the diameter of the switch some by sanding but in the end used a G-cramp, with a bit of wood between the terminals to pull the switch into the lock, lining up the lug with the slot in the lock body first. There is absolutely no danger of the switch turning.
I created confusion for myself till I worked out that the switch operates in 4 positions with the last being spring return to connect power to the starter solenoid. In fact the wire attachments to the terminal was the same as for the original switch, all checked using a continuity setting on the avo.
I have yet to find a suitable place for the relay and a (reversible, tidy) method of connecting the brown wires.
When it came to fitting into the lock body it was a b****dy tight fit. I actually tried to reduce the diameter of the switch some by sanding but in the end used a G-cramp, with a bit of wood between the terminals to pull the switch into the lock, lining up the lug with the slot in the lock body first. There is absolutely no danger of the switch turning.
I created confusion for myself till I worked out that the switch operates in 4 positions with the last being spring return to connect power to the starter solenoid. In fact the wire attachments to the terminal was the same as for the original switch, all checked using a continuity setting on the avo.
I have yet to find a suitable place for the relay and a (reversible, tidy) method of connecting the brown wires.
Jerome Lunt
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT
1970 S2 FHC - Dark Blue, Red Interior, MX5 Seats
2008 MX-5 NC PRHT
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