Well, i got a check engine light (#9, water thermosensor). So I took off the UIM and it looks plugged in securely... but then I see this "extra" wire just laying there doing nothing.

It comes out about where the PD is and extends only as far as the alternator and is black and round with a single wire/pin. It seems to not have a mate and maybe (hopefully) it was setting off that code...

Anyone know WTF this is?

sorry I don't have a digicam right now..

 

Is it the firewall ground? I can't think of any wire I've ever seen in that location.

 

The special wire to two secret options that some cars have: passenger ejection or self destruction
Plug it into something and let us know what happens
Use a DMM and measure the resistance from the connector to the battery negative side. If it is zero or really low, as mentioned, it could be an additional ground wire. If it isn't, are you sure there isn't something unplugged laying around?
Also, I have run across some plugs where a stray wire disconnected itself. Make sure that it doesn't belong to a plug connection somewhere.

 

hahahhaa i'm so stupid.

I shoulda searched lol!

I found the exact same question in this thread I found : https://www.rx7club.com/forum/showth...t=mystery+wire

Appearantly, it's either for a knock sensor or (more likely) an electric fan thermoswitch. I have neither .




BTW- I found out what was wrong w/the water thermosensor. The connector to it was screwed. The metal clip that hooks the pins got pushed back so it wasn't making contact. hehe.... simple fix

PS - for future searchers of the mystery wire, here are some key words : what wire mysterious wire unknown wire strange wire black round wire weird wire where does this wire go unhooked plug round plug

 

Another mystery solved. Have a scooby snack.

 

hehe... I like the keywords!