Just got this truck and unfortunately the previous owner is no longer around to ask questions so here I am. I found the unconnected plug right above the AC dryer and I’m curious what it’s for. I posted a picture to go along with it. Any info is great, thanks!

 

That's the old school diag plug but it's weird to see this on a 96 which is OBD2.

 

Have a look in the factory service manual, In the back there are diagrams of every plug used.

 

I found on the epa.gov website that it was federal mandate that all vehicles manufactured after 1/1/96 had to be OBD2 but my truck was manufactured in May 95 so that probably explains why it’d be OBD1 still

 

Does you PCM have one large plug, or three smaller ones?

 

I have that same plug in the same place on my '96 Ram 2500 4x4 5.9 magnum engine truck. I was told by a former Dodge mechanic that it was the old style OBD1 plug even though I have the OBD2 plug under the dash. The production date of my truck is 11-1995.

 

three smaller ones

 

Ok, that's OBDII..... Weird. Wonder if the old connector works as well....

 

I was hoping that it worked, but when I tried to connect the Snap-On MT2500, the scanner wants to connect to the OBD2 port under the dash when I use the VIN information to identify the truck, as I had hoped to pull ABS information, but the scanner wasn't able to access ABS related data at least through the OBD2 port. I might have to try telling the scanner that the truck is a 1995 and it might want to connect via the other OBD1 port.

 

For my current project, "diagrams of every plug used" might be helpful, as well as other electrical components (i.e. TCM, DRL module, the 26pin J/C 1 & 16pin J/C 2 in the PDC). I've seen references here to a service manual link in many other posts here but when I tap it, downloading starts on a 2,889 page PDF. I know such a manual would be great to have and I would be grateful to access it. There's no telling how long it will take to finish via 1-bar on 4GLTE soooo...... I guess the best I can do about that is public WiFi at Monday night's poker table.

For my current project, I'm making a relay's wiring harness for DRL, which my 01 1500 Laramie 5.9 (seemingly) doesn't have. I'm about to write a separate post for that.

Thanks y'all.