Tyler Posted January 13, 2021 Share Posted January 13, 2021 I think I found my REAL problem. It's not an amperage deficiency, requiring 3G but something else. Backup lights never worked since I got the truck. Switch on tranny replaced and still no workie workie. Then, I removed the trailer wiring harness which was a plug-n-play splice at the tail light connector back by the bumper. Reverse lights worked. I celebrated. I finished the Sniper install. Now they don't again... Also, when the headlight switch is on, tail lights are not, license plate lights are and brake lights do not energize when I step on the pedal. When headlight switch is off, brake lights work. When truck is put into reverse, the brake lights come on instead of the reverse lights. I did not switch the bulbs into the wrong sockets, I promise! 138 days until I take a two month, 5,000 mile, one way, cross country trip Combing the schematics but I'm a mechanic, not an electrician... Link to comment Share on other sites More sharing options...
old55pete Posted January 13, 2021 Share Posted January 13, 2021 Sounds like you have a ground issue. Like all of the lights are grounding through each other to come on. At the back of the frame in the harness there should be a Black wire with a white stripe, strip some of the insulation and add a temp ground to the frame and see if the lights work correctly. Link to comment Share on other sites More sharing options...
Tyler Posted January 13, 2021 Author Share Posted January 13, 2021 Sounds like you have a ground issue. Like all of the lights are grounding through each other to come on. At the back of the frame in the harness there should be a Black wire with a white stripe, strip some of the insulation and add a temp ground to the frame and see if the lights work correctly. Will do. Also, my hazards work until I put the key in run and the transmission into reverse. Link to comment Share on other sites More sharing options...
old55pete Posted January 13, 2021 Share Posted January 13, 2021 Will do. Also, my hazards work until I put the key in run and the transmission into reverse. I am assuming that is because they are loosing their ground. Link to comment Share on other sites More sharing options...
grumpin Posted January 13, 2021 Share Posted January 13, 2021 I am assuming that is because they are loosing their ground. I’ve had 2 or 3 trucks that I had to redo the trailer lighting on. On my 86 I had problems with the ground as Steve said. Can’t remember what exactly it was doing. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 13, 2021 Share Posted January 13, 2021 I’ve had 2 or 3 trucks that I had to redo the trailer lighting on. On my 86 I had problems with the ground as Steve said. Can’t remember what exactly it was doing. Yep, I agree. Electrical problems that make no sense, at first blush, are almost always a ground problem. Link to comment Share on other sites More sharing options...
FuzzFace2 Posted January 14, 2021 Share Posted January 14, 2021 Yep, I agree. Electrical problems that make no sense, at first blush, are almost always a ground problem. I see you have a 300 six and the ground cable from battery run along the top of the frame with a tab grounding the frame and then on to the top starter bolt. I would remove that bolt and clean the frame & tab and bolt it back down and see what you have. What bed does the truck have? I forgot the year but the early trucks did not have a ground wire in the frame harness like the documents show going up to the firewall behind the radio. The style side had a ground wire at each tail light and screwed to the bed behind the lights. I don't know what the flare sides had but I ran a ground from each light, plastic housing, thing to 1 of the light housing bolts as the bracket is metal and bolted to the metal bed side panels. Now my bed floor is a custom ribbed metal floor so the bed sides are grounded to it and the floor to the frame. I have not had any issues with rear lights and I have 1 of them Tee's for trailer lights between frame harness and tail light harness. I am with others it a ground issue. Dave ---- Link to comment Share on other sites More sharing options...
Tyler Posted January 16, 2021 Author Share Posted January 16, 2021 I see you have a 300 six and the ground cable from battery run along the top of the frame with a tab grounding the frame and then on to the top starter bolt. I would remove that bolt and clean the frame & tab and bolt it back down and see what you have. What bed does the truck have? I forgot the year but the early trucks did not have a ground wire in the frame harness like the documents show going up to the firewall behind the radio. The style side had a ground wire at each tail light and screwed to the bed behind the lights. I don't know what the flare sides had but I ran a ground from each light, plastic housing, thing to 1 of the light housing bolts as the bracket is metal and bolted to the metal bed side panels. Now my bed floor is a custom ribbed metal floor so the bed sides are grounded to it and the floor to the frame. I have not had any issues with rear lights and I have 1 of them Tee's for trailer lights between frame harness and tail light harness. I am with others it a ground issue. Dave ---- Thank you, All ! I don't know what I would have done without all of you helping me through. I'm extremely grateful to have found this site. Ground issue indeed. I took the ground (black / wht stripe) wire and stripped a small section, then made a jumper with alligator clips and grounded it to the frame. All lights work normally, now. Just need to finalize the new ground wire properly. I'll go ahead and clean up the frame ground under the hood as recommended. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 16, 2021 Share Posted January 16, 2021 Thank you, All ! I don't know what I would have done without all of you helping me through. I'm extremely grateful to have found this site. Ground issue indeed. I took the ground (black / wht stripe) wire and stripped a small section, then made a jumper with alligator clips and grounded it to the frame. All lights work normally, now. Just need to finalize the new ground wire properly. I'll go ahead and clean up the frame ground under the hood as recommended. Glad it worked, Ty. On your truck that wire should go back to a ground to the firewall ahead of the radio. You might check that it is in place. And then check that there is a ground wire from the back of the engine to the firewall close to if not on the windshield wiper motor. Link to comment Share on other sites More sharing options...
Tyler Posted January 16, 2021 Author Share Posted January 16, 2021 Glad it worked, Ty. :nabble_anim_claps:On your truck that wire should go back to a ground to the firewall ahead of the radio. You might check that it is in place.And then check that there is a ground wire from the back of the engine to the firewall close to if not on the windshield wiper motor.I just started it up and backed out of the garage. Now having same issues with ground wire in place. I wire wheeled down to bare metal before I put the ground in place. Shaking my head... I'll check the other things you mentioned. On Sat, Jan 16, 2021, 8:21 AM Gary Lewis [via Bullnose Enthusiasts Forum] <redacted_email_address> wrote: Link to comment Share on other sites More sharing options...
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