Running Lamp relay and mystery wire

WAID

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As I am looking into the wire schematics for my '86 to get a better understanding before jumping into the running light relay mod, I see some additional relays on the schematic. One is a "trailer exterior lamps relay" which I was able to locate and a "marker lamp relay" which I am unsure if it exists. What exactly do those two relays do and do either of them replace the running lamp relay mod? I'm not super sure on my reading of these schematics and I am having trouble looking up what some of the codes mean.

Also I have a mystery ground near the wiper motor that doesn't connect to anything. What should it be connected to? It is the grey connector looped to the right of the wiper motor.
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79jasper

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You mean headlight relay mod?
The running light relay goes with the trailer package, iirc. (And maybe only duallys?)

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WAID

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You mean headlight relay mod?
The running light relay goes with the trailer package, iirc. (And maybe only duallys?)

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Did the headlight mod already. Was looking at the running light mod in the tech articles. I'm not clear on whether that also applies to my truck. It looks like the roof marker lights go through the switch but the front side marker lights go through a relay near as I can tell on the diagram but I am not finding that relay on my truck, as the location of the connector is a little vague, "L.H. side. in engine compartment. I can find the trailer exterior lamps relay in the location described on the schematic, "L.H. fender apron, near dash. Trailer lamp relay" Maybe the trailer light relay is an alternative to the marker light relay? It looks like it powers all of the marker and parking lights with the 14 BR wire(I know brown but does 14 refer to gauge or circuit number?) but I may be reading the schematic wrong.
 

chillman88

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I know on my 91 dually the only thing the trailer light relay powers is the markers on the dually fenders, the 3 lamp ID bar under the tailgate, and the trailer plug. I know this because when you get water in the trailer lamp relay your fender lights stay on all day when you get to work.....
 
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