Car won't turn off!! Burnt ignition switch wiring. WTF?

jules · Postby **jules** » Mon Oct 14, 2013 9:13 pm

Well, that was fun. Got home, switched off the car and it still runs!

Upon pulling the ignition switch wiring I find the below. Looks like the lugs have melted the plastic plug and are shorting.

Is this just an age thing, or has someone else experienced this? If so, any idea on the best way to go about replacing the plug?

Thanks

davekmoore · Postby **davekmoore** » Mon Oct 14, 2013 10:03 pm

Pure guesswork here but:

It looks like you have an NA, so at least 16 years old. Electrical stuff can go wrong at that age in any car. Thank your lucky stars you don't have a 16 year old French car - or a 3 year old one for that matter.

It's odd that those connections are that badly affected. Shouldn't a fuse or a relay have tripped out before that happens?

jules · Postby **jules** » Mon Oct 14, 2013 10:51 pm

From memory the fuse for that circuit is a big one!

jules · Postby **jules** » Tue Oct 15, 2013 8:58 am

The symptom was pretty odd. The car would keep running with the key out. The ignition lights were illuminated on the dash, however all accessories were switched off. Sounds like the 12v constant feed to the IGN lead were touching...just.

For now I have it plugged back in with the shrouds off and the car is working as normal. I have not done any electrical work on the car in this area.

I am hoping that perhaps being an "old girl" ('91 Malibu), that this is just a case of resistance built up over time.

I'll need to investigate repair options (maybe I can get a loom from a wreck), but was interested in whether you guys think this could be in any way age related, or whether I should get out a multimeter and start testing?

Cheers
Jules

emily_mx5 · Postby **emily_mx5** » Tue Oct 15, 2013 9:48 am

Do you have an alarm/immobiliser fitted? They always cause electrical problems, I would take it out.

The copper contacts in the ignition barrel get worn out and corroded, there is a god article on miata.net about cleaning it.

The loom is part of the car harness, doesn't unplug. You would have to cut the old plug off and solder/crimp in a new one.
You could probably find a new plug online somewhere that sells automotive connections, maybe even Narva make one.

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jules · Postby **jules** » Thu Oct 24, 2013 3:17 pm

Big thanks to Eric and MX5 Plus!

a: 1x Narva 6 pin terminal block with lugs (also available from Supercheap)
b: 1x Slightly used ignition switch
c: 1x Precision skilled soldering job from yours truly ;-)
=
d: Factory perfect result!

Ta Da!