Hey guys, so the other day I removed my driver side fender and noticed a little shade-tree wiring done by someone that was not me.

There’s a very thin factory wire (blue/orange tracer) that appears to have—at one point—gone from the main harness from PCM all the way the through to AC/Clutch relay. Well, it was just snipped about 2” short of the relay, and the remaining wire was butt-spliced with a random, thicker yellow wire that runs across the firewall harness where it is butt-spliced with a brown wire that runs (along with 2 blue wires) into the connector for what I can only find to be the heater/AC cycle switch or suction switch.

What are the benefits of doing this to the truck? Or is there a common gremlin they were bypassing? Any help would be appreciated.

1993 D-250

Addl photo

Passenger side where yellow wire spliced into harness’ brown wire

Better view

The WOT /AC clutch relay and where the yellow wire originates

Additional

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Someone bypassed the PCM. Why I can't tell you. PCM may have burned out. You could reconnect to find out.

This is a ground signal. You may want to see this thread to add a thermostat between those wires

 

i’ve got re-hooked up like it originally was I had a new PCM installed or a rebuilt one from a reputable company. What does the a/c cycling switch do?

 

Regulates temperature and keeps the evaporator from freezing up into a huge ice cube.

 

So your looking for a PCM for your truck? Your post is hard for me to understand…
If s you need one, I have some, along with about any other 1st gen OEM part.