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MG MGA - 1500 turn signal switch voltage out is low

Good evening,
I am able to get the turn signals to work if I bypass the switch's innards and put 12 volts on the switch's output terminals, or if I jump 12 volts to connector 1 on the relay.

But the switch only puts out 3 volts, which will not operate the relay. 12 volts into the switch, 3 v. out. New switch. What am I missing??

Thanks,
Jack
John Bissett

If it's a brand new switch it 'might' have some grease on the contacts, I'd give it a good workout switching it on/off a few times and it might clean up ok
William Revit

Jack,
have you perhaps closed off the air bleed screw too much?

Have a look at attached PDF or this link from Brown & Gammons, see page 2 of the leaflet too. - https://www.ukmgparts.com/userfiles/pdfs/amk5607.pdf
Nigel Atkins

Thanks for your suggestions. The switch works fine - shuts off as it should, and passes 12 volts thru nicely IF the switch is fed from a different 12 volt source.

It is supposed to be fed from the B terminal of the petrol gauge; however the tank is empty (drained in 2019 before I started taking the car apart) so there is no impedance through the gauge. I assume that is confusing it. When I connect voltage from another source (switched side of ignition switch, for example) it works just right. So I will put a little gas in the tank and see if that cures it. If not, I will pull 12 volts from the ignition switch key-controled side.

Happy to have that figured out!!

Thanks for your help, and good luck,
Jack
John Bissett

Jack,
I'm not an electrician or expert in anything and don't know my own car's wiring let alone an MGA but that live in doesn't sound right to me. Have a look at a relevant wiring diagram in your Driver's Handbook or elsewhere (Barney's site?) to check.
Nigel Atkins

Sounds like a bad connection on the power wire to or from the fuel gauge, so it loses voltage when trying to draw current.
Barney Gaylord

This thread was discussed between 26/07/2022 and 28/07/2022

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