Instrument Cluster and Parking lights

[Joe1shoe]

I've read informative info on other posts about IC and Parking lights. My truck is a 87 sierra Classic. I'm the original owner. So if its wrong. I did it. I currently have all my lights working except the parking and IC. Fuse was blown. Replace fuse. Fuse blew. OK we have a short. I took out the headlight switch and tested it. seems fine. I see the orange wire from the terminal block feeds power to the two terminals with brown wires when the headlight switch is pulled out. One brown wire feeds the parking lights in the front of the truck. The other brown wire heads over to the radio along with one of the orange wires. It appears that when the owner replaced the factory radio with a digital classic radio. He attached the orange wire to the radio power input and the brown to a radio ground. I unplugged that connection and the fuse no longer blows and I have front parting lights. But I have no rear parking lights, nor IC, or Radio (obviously). I may have been without parking lights for a year. I don't know. But I would have swore I had dash lights. I only drive it a dozen times a year. So I can not confirm that.

The real question is.... Where exactly does that brown wire that needs to get to the IC and rear parking lights go when it leaves the headlight switch? It clearly has a factory connector and is paired with the orange wire headed for the radio. I don't have the original radio. The new radio did use the factory harness plug that ran to all the speakers plus 3, maybe 4 wires that go back under the dash. Non of those are brown. Maybe one of them is where brownie should have gone. Don't know.

Need some help with the life cycle of that brown wire from the headlight switch, to radio, to IC, to rear parking lights. I stared at a wiring diagram a while. didn't help me. I put it down and called you.

Thanks

 

[Bextreme04]

Looking at a wiring diagram for an 87, it looks like the Orange should be ACC Radio power. The Brown could be for backlight to the radio, its not the best way to do it, but that could be what was done. If you wanted an adjustable backlight on the radio, it should have been spliced after the IC backlight rheostat. The parking lights are run from the same brown, but it looks like the IC lights are run from the green wire out of the light switch.

 

[Joe1shoe]

At the firewall, engine side, I see there is a plug for Front light harness and a plug for the rear light harness in that terminal block. Do you know how the brown wire is supposed to get there? If I disconnect where it is. I don’t know where to plug it in under the dash.
On the IC lighting. Does the green go from the headlamp switch to the IC via the big terminal plug in the back of the IC?

thanks

 

[Joe1shoe]

Update on this. Bextreme04 put me in the right direction. I disconnected the hot brown from the headlamp switch to the after market radio. It was attached to a ground anyway. That fixed the short. I needed to figure out the next issue. IC had no lights. To get the IC out. it was just easiest to take the dash pad off, then the IC cover. Then the IC. Cudos to whoever suggested lube on the speedo cable to allow the IC to come out farther to get your big paw in there. it works. The IC issue turned out to just need some tweaks. clean contacts on the IC plug, test, a little bend of a tab here and there to get all the lights working. Now the parking lights.... The front parking lights came back when I fixed the short. The rear parking lights did not. I went to the bulkhead plug at the firewall. when you take it apart. there are plugs to harnesses stacked together. Rear harness, front harness and all the engine harness. So I was confused why the front parking lights worked but the rear did not. It wasn't the harness or a ground. Checked those twice before I came for help. It appears that the parking light terminal in bulkhead connects the brown wire from the headlamp switch to both the front and rear harness. If i had some experience with the wiring diagrams I might have known that earlier. But its what we know now that matters. So. I think I'm fixed.

...except one little thing. I pulled a wire out of the connector at the rear bumper. Who knows how to get those 4 prongs out to reattach the wire to them?

 

[Jethro224]

Usually you can poke a wire or pointy thing in there to release a tiny lock tab on the brass. Probably from the front.

 

[Joe1shoe]

This is in the weeds a bit. But I have a feeling i'll either destroy the connector or wont be able to replace the wire in the pin.

Is the male connector a 12015024 housing? and can you tell me the PN of the pins that go in it?

 

[sdewolfe]

Part number 12015024 is the Weather Pack number for one side of the connector, using male pins # 12089040. The mating side of the connector is 12089040 with female pins # 12124580. But you will probably need new weather seals too. If so just get a $5.69 kit from allelectronics.com that has everything for one 4 pole square connector.
https://www.allelectronics.com/item/wp4s-14/4-cond-square-weather-pack-connector-kit-16-14-ga/1.html