Hi,

This is off a 90 F-250 7.3 on the driver's side. I know it's obviously a relay, but what is it called & is it related to the guages not working? Thanks

 

It looks like a terminator cap. Room for improvement lmao! Not sure what it goes to but I have one and my buddies has two near that location.

Edit that coffee can is usually on the passengers side as well

 

can u zoom out the pic

 

On my 89 the coffee can is on the drivers side and that looks like an ECC relay.

 

What exactly does the ecc relay do?

 

The correct Ford term for it is actually TECA relay, and it powers the PCM (electronic brain box) that controls your E4OD transmission. If you do not have an E4OD transmission, then it could be the running lights relay that is part of the factory towing package. If you do not have a factory towing package either, then this relay does not really exist in the know universe and is merely a figment of your imagination, likely as part of some wiring-related nightmares you may have had recently or are about to have in the near future

 

LCAM you really know how to put a bright side on things lol.