Couple snipped wires, need help identifying them, 89 4x4 2.9L Auto

[eightynine4x4]

Part 1: I found this months ago behind the battery but haven’t been able to figure it out using the electrical diagram in Haynes for some stupid reason. Anybody recognize what it used to connect to? Did it just go to the battery negative? Here are pics I took when putting in a new battery.
It’s black, has been snipped, it enters a 3 pin connector behind battery and that connector has another black wire that goes to the connector I’m touching in second pic which mounts to the top of that black cylinder (i don’t know what that is TBH), and that same connector also has a very long black wire that goes all the way back by the firewall and connects to the a/c compressor’s outer chassis. Not thinking this snipped wire is definitely ground because there are other signals in these connectors but it very well seems it could be ground.

Part 2: There’s a relay of some sort on the drivers side firewall and 2-line conduit is coming from it and is quite long and goes nowhere. Aftermarket something? I looked up the Bosch part# and it’s a generic relay. The plastic conduit used to dangle down along the drivers side wheel well and hang down as if it was a fluid overflow which is why i never thought it was electrical.

 

[ericbphoto]

Connector in second photo is the pressure switch on the A/C receiver.

The relay in the third photo may be the WOT (wide open throttle) relay which turns off the A/C compressor when your throttle is wide open. Don’t quote me in that. I’m basing that on your statement that it’s wires are going to something A/C related near the firewall- probably the other pressure switch near the condenser. The compressor is a belt-driven piece mounted on the front of the engine.

That cut wire may very well be a ground. But you will probably need to find out what it goes to to figure that out.

The most helpful book you could get is the EVTM for your truck. That is the electrical and vacuum troubleshooting manual with all wiring diagrams, connector and component locations. Connector pin outs and circuit descriptions. Usually available on ebay

 

[eightynine4x4]

Connector in second photo is the pressure switch on the A/C receiver.

The relay in the third photo may be the WOT (wide open throttle) relay which turns off the A/C compressor when your throttle is wide open. Don’t quote me in that. I’m basing that on your statement that it’s wires are going to something A/C related near the firewall- probably the other pressure switch near the condenser. The compressor is a belt-driven piece mounted on the front of the engine.

That cut wire may very well be a ground. But you will probably need to find out what it goes to to figure that out.

The most helpful book you could get is the EVTM for your truck. That is the electrical and vacuum troubleshooting manual with all wiring diagrams, connector and component locations. Connector pin outs and circuit descriptions. Usually available on ebay

Ok thanks for the pointers. My A/C compressor has always had its belt off since I got the truck a year ago. The PO definitely wanted to delete the strain of AC on engine. I think it may be that they deleted related electricals too. But I can’t assume that all the remaining disconnects in engine bay are all AC related. There’s not much, basically just whats here. Gotta figure out how it’s supposed to be and also what the AC delete mod actually is so I can clearly label the wires for future hookup. I’m fine without AC in general. But I have to make sure something more engine related is sitting broken.