tgreese wrote: ↑Fri Jan 31, 2025 10:41 am Switching between the brakes and indicators is handled by the turn signal switch.
You wrote a lot but it does not help. You need to measure and compare to the wiring diagram.
There are lots of diagrams online if you search. Jeep uses a GM column, same as GM cars. I can't recite how it works from memory, but you can look at the diagrams and the TSM and trace it through. Recall I suggested that you needed to use your multimeter and trace the circuits.
Sorry, there is no shortcut for this. Diagnosing electrical problems requires the car be in front of you where you can measure the circuits.
You don't need to understand what's inside of the switch. There are inputs and outputs that you can measure.
You could fire the parts cannon and replace the turn signal switch. That's the most common problem after grounds. No guarantee that will fix it though.
devildog80 wrote: ↑Fri Jan 31, 2025 1:23 pm Suggest checking the rear light assembly, to be sure it is grounding like it should, then go from there.
tgreese wrote: ↑Fri Jan 31, 2025 4:52 pm A simple test light can often be enough.
https://www.amazon.com/JASTIND-Automoti ... -Indicator
-or-
https://www.harborfreight.com/612v-circ ... 63603.html
Likely also for sale at your local parts store.
Just follow the signal. You'll still have to read the diagram to find which wires connect to the turn signal switch connector where.
Two things: trace the circuit through on the diagram, then measure. Measure, measure, measure.
tgreese wrote: ↑Sat Feb 01, 2025 5:59 am You need to be more specific with your question. 15, 16, 17 could be the model number or could be the circuit number. Model numbers are shown in section 1. The circuits are numbered in a table with the diagrams. On the diagram you;ll see something like "16 WT 18" for circuit 16, white wire, 18 ga.
devildog80 wrote: ↑Sat Feb 01, 2025 3:00 pm On these old rigs, many times what was built at the factory, requires grounding through body pieces/parts bolted/welded together. Over time, the bolted pieces can oxidize between the parts, and lose grounding.
So when chasing grounds, feel free to add any you think are needed between body parts, frame, engine, battery, and give the electricals a fighting chance to work as intended. Hurts nothing, and if nothing changes nothing lost for your efforts, as they will be helpful with grounding issues you do not even know you have yet with other lighting on the truck. Found this out when working on my own rigs.
And I do agree, if the RR tail light is working correctly, the LR should too, but not always. Could be in the steering column, or not. Just need to keep at it, and you will find the issue :/
devildog80 wrote: ↑Sat Feb 01, 2025 5:00 pm Can be simple as a 4-6" 10-12 gauge wire, eyelet on each end, star washer screw on each side. Or existing screw/bolt on each side, make the wire with eyelets to fit and connect, making sure metal & hardware are super clean where eyelets contact.
Concept is to have the wire/cable connected from one piece of the rig to another. Lets use front grill, fenders, frame, battery, as an example.
Example
Mounting screw for headlight mounted in grill....
grill to negative battery post
OR...grill to fender to negative battery post
OR..grill, fender, frame to negative battery post..
OR..grill,fender, firewall, negative battery post
You are creating a pathway, like the little line puzzles in kids books, enter here and find path to center of puzzle. You are doing this with your grounds. Start at battery negative terminal, take your ground wire path connected between them out to all metal pieces on the truck with the short wires, and they will connect back to your negative battery terminal.
You can use buss bars for connection points, to allow multiple wires more easily, mostly around the engine bay and interior of the rig.
You get the idea.
Here is one on mine, next to battery in engine bay. This connects from battery negative, then I have a wire into my cab, and another buss bar in there, for anything needing grounding inside. Gauges, switches, sound, etc.
20221127_151219 by Scott Weckerly, on Flickr
20221127_142915 by Scott Weckerly, on Flickr
tgreese wrote: ↑Sun Feb 02, 2025 12:39 pm Ya know, adding extra grounds won't hurt. If you want to add a dedicated ground bus where you can tie in your ground wires, go ahead.
However, both the body and the chassis are large conductors that will abley carry ground current back to the battery. A big wire has much less resistance than a small wire, and the body and chassis are very large, much larger than any of the wires used in a car. What they lack in conductivity compared to copper is likely made up for to large degree by shear size. More certainly a ground problem comes from corrosion or looseness in the ground connections, rather than some deficiency in design.
I'd suggest refreshing all the factory ground connections first, rather than add a lot of redundant wire. If the taillight housing depends on metal-to-metal contact, it should be clean and firm. You can add local ground jumpers to the chassis or body if you wish. New connectors, proper crimps and solder (if so inclined), new hardware and new shakeproof washer. But a solid local connection should be enough IMO.