quick question - what is this?

[wakingtowinter]

Anyone know what this harness is for? Comes up on the fender wall right next to the starter solenoid. I can't see anywhere it connects to, is there supposed to be a relay on the end of it? Thanks

 

[crbnunit]

That is the computer jack. Code reader plugs into it. The single wire is the ground.

 

[adsm08]

Yup, CRB is right, it's your Diagnostic connector. Roughly equivalent to the OBDII port, but for EEC-IV.

There should be a little 1 wire plug near it that you need too for the ground.

 

[wakingtowinter]

Cool, thanks

 

[BRUTUS_T_HOG]

also at one point in your trucks life it used to have a black cover that went onto these plugs to keep them clean

 

[Nhaz]

I have seen that black cover attached to the bottom of the fuse box sometimes. and sometimes not.

 

[cody93]

its a diag port. heres some more info http://www.therangerstation.com/tech_library/OBD_I.html