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Turn signal switch
Posted: Sun Mar 15, 2020 6:44 pm
by RollyTG
My turn signal switch (indicator switch?) is, like most of them I'm sure, broken. The plastic canceling apparatus is missing some pieces. I think there are some other little components missing too. Can any of you offer me the benefit of your experience with this problem. Do I just fork out the $200+ for a new one, or is there a more economical solution? Is the same part used in other models - maybe XJ6 or such? Thanks.
Re: Turn signal switch
Posted: Sun Mar 15, 2020 8:38 pm
by cass3958
The part number for the switch assembly on the early cars is C25257 and on the laterS Types and the 420 cars C25555.
The XJ6 series one part number is C35091 so not the same so I would assume without checking them all that the part number is just for the S Type and 420.
I would suggest a second hand unit would be cheaper but the plastic does degrade and all second hand units are likely to have the same problem brewing that you have at the moment.
Re: Turn signal switch
Posted: Mon Mar 16, 2020 8:17 pm
by RollyTG
Thanks Rob. I will just bite the bullet and order a new one. It's only money.

Re: Turn signal switch
Posted: Mon Mar 16, 2020 8:28 pm
by Glyn Ruck
Make sure you get the later switch. Some earlier units were non self cancelling.
Re: Turn signal switch
Posted: Tue Mar 17, 2020 12:51 pm
by RollyTG
Thanks. I've ordered C25255, which according to Barrat is the correct one.
Re: Turn signal switch
Posted: Tue Mar 17, 2020 9:52 pm
by Glyn Ruck
That's the self cancelling type!
Re: Turn signal switch
Posted: Thu Mar 26, 2020 3:26 pm
by RollyTG
I have received the new switch. It looks somewhat sturdier than the old one, but the wiring is not identical. The new one has a black wire where the old one does not. Electrical stuff is something of a mystery to me so this is going to be a learning experience for me. Can anybody offer an opinion as to why the old one does not have a black wire and maybe suggest what I should do with same when I install the new switch into the car? Thanks.
Re: Turn signal switch
Posted: Thu Mar 26, 2020 5:02 pm
by John Quilter
On my 3.8S wiring diagram the switch shows two wires that go to ground. On Lucas wiring diagrams black is usually ground wires.
Re: Turn signal switch
Posted: Fri Mar 27, 2020 12:12 am
by Glyn Ruck
Black are ground wires. Wiring colours can be inconsistent. Best to wire by function. Early versions had fabric insulation.

- Indicator switch.JPG (45.09 KiB) Viewed 2639 times

- Indicator - Copy.jpg (83.24 KiB) Viewed 2639 times

- Indicator sw1.jpg (320.13 KiB) Viewed 2638 times
See here for detailed S Type wiring diagram.
http://www.jagstyperegister.com/images/ ... g-page.jpg
Re: Turn signal switch
Posted: Fri Mar 27, 2020 1:53 am
by RollyTG
Thanks Glyn. I am making progress learning to interpret the wiring diagram. My new switch looks just like your picture, but I don't have the white plastic ring part that looks fairly essential. I might have to get onto Barratt's about that. My old switch has two cloth wrapped wires from what appears to be the headlight flasher part. they are black under the cloth. One of those goes to a double purple wire in the harness - ah, I see it now. in the diagram the light flasher is shown in a separate part of the picture. Progress.