Topic: 1985 efi runner flickering lights strange problem

[85efirunner]

my 1985 runner has been doing some weird stuff lately n i wanna kno if anyones ever seen this wen my key is in the ignition lights off if i depress my brake pedal the dash lights come on relitive to if my foot is on or off the brake pedal this also happens with the truck running with the lights off. now with that being said when the head lights are on my dash light stays on and doesnt change relitive to my brake pedal being depressed but as i drive down the road my taillights flicker randomly (thats my major concern here) i looked up the wiring diagram and didnt really get far with that and i looked at my brake switch and it was a little corroded so i replaced it solely because it was so cheap this did not fix it so if any one knows what it could possibly b i would love to hear what u think my dad thought it was a reverse bulb mixed up with my tail light bulb so i looked at all the bulbs and they are all the correct part numbers in the correct position so thats not it either

[twistedtoy92]

does it have a trailer plug wired into it?

[Cheesemaker]

Check the sockets in the taillights.  Sometimes they rust up/corrode, and cause grounding issues, and will back feed up to the dash.     Seen this alot around here on the coast. 

[jimbo74]

check your grounds, also check the harnesses behind the dash if you can

[Rocksurfer]

Somewhere in the system you created a loop, have you recently installed an electrical component like aux lights, new stereo, etc. etc. If you have try disconnecting the new component and see if it goes away. Plumbing your new component to the wrong wire can create a multitude of electric gremlin's.

[85efirunner [OP]]

ok first off thank you for ur guys input i have replaced some bulbs back there and they were not corroded i will definitly re check all of them and i have wired a new deck and 2 subwoofers so i will disconnect them and see what happens the most intersting one is the trailer comment when i got under there and looked at the harnesses i noticed this black box ductaped behind the trim panel that is to the left of the pedals and right uner the fuse box idk what that thing is it has a on off switch on the top and it appears to do nothing is that maybe a trailer switch deal? i will reply again once i have tryed all of these

[OOPS]

i noticed this black box ductaped behind the trim panel that is to the left of the pedals and right uner the fuse box idk what that thing is it has a on off switch on the top and it appears to do nothing is that maybe a trailer switch deal?

It sounds like that may be an old alarm system brain.

[Cheesemaker]

After re-reading everything.  I would look into the headlight, and brake light grounds under the dash.  They seem to be tied in together.  So, maybe one or the other are loose.  Sometimes, they use a single ground wire for multiple items.