What Plug Is This?

[dirtdog 4]

Any ideas? Thought it might be the fan test plug but apparently not..(whatever plug I try .. no fan).

 

 

Sorry this is so vague.. and i'm also sorry but.. somehow inbetween taking the picture and uploading it, somehow it's turned it's self around. The rad is at the top of the pic.

 

 

[pug_ham 245 3 Cars]

Water sensor in the fuel filter housing maybe?

 

Can you read any wire numbers near the plug?

 

Iirc there might be a spare plug on the STDT loom so it might be nothing.

 

g