DC Electric problem-Rear Lights Fuse-2016 300GK

[Rich T]

I also have a 2016 300GK, I hope you get the prob fixed, you have done everything I can think of. The reason I'm responding is that I was just in this area working and when you get the short fixed if you want to move the 3 switches it is not that hard. I moved my fan control up and put the 3 light switches under it on the side of the cabinet facing the entry door, much better location IMO. Hardest part of project was coming up with something to cover the hole left by the switch block underneath where it was removed. I cut a 3/16 piece off the face of a 3/4 board I had that was already finished about the same color. Wish I could do the other 3 switches down by the pantry door, but it doesn't have a hallow area just one thickness of paneling.

I know this was no help with your problem, sorry, good luck.

Rich

[ACDW-Ottawa]

Thats a lot of information so I'm a bit confused, but I'll try to help.

BTW: Make sure you are using good quality fuses, preferably slow-blow fuses that will withstand surge current (gives you test time in case of a short). Cheap fuses blow too quickly, even with minor current surges. If you are using cheap or standard fuses it could be why they blow immediately compared to the first fuse that may have been a good quality one or slow-blow type (just guessing to explore all possibilities)

FYI: It may not only be a bad wire causing the problem. It could be a defective device or wire shorting to ground at a terminal.

I'm assuming the following so you will have to correct me in your response:
a) when you refer to your volt/ohm meter, I'm assuming you have a recent digital multi meter (DMM) that also measures DC Amps
b) You now have the whole circuit apart so that you isolated each switch, light and wire?

So let's start at the beginning and take it slow and simple.
Assuming you took apart your system, set your DMM to 20Vdc (or similar range). Measure the voltage at these points:
1) Measure your battery voltage (lest see what your baseline battery voltage is - should be approx 12.6Vdc or better)
2) Measure the electrical panel voltage across the Negative & Positive rail
These two voltage readings should be the same (approx)
3) Measure the voltage at the hot side of the fuse terminal for the "rear light" circuit that your blowing fuses (black lead on the Negative rail)
This voltage should also be same as the electrical panel voltage in #2
If the voltage is good (same) in step #3 , then the wiring to that circuit in the electrical panel is good.
4) If you got this far, connect a fused load (i.e. a light with an appropriate fuse) between ground and to the hot fuse terminal (that you just measured)
If it works, you know that circuit is working and can proceed step by step to test the remaining parts on that circuit.
4b) Set your DMM to DC Amps and connect it in series with your fused load to measure the current and record it in case needed at a later time (easy test while this test load is set up)
5) Remove your test load and keep it for later testing
6) Find the first wire in your "rear lights" circuit coming from the electrical panel and make sure it is not connected to a device (so no loads or devices present), insert a 15Amp fuse to see if it blows
7) If the fuse blows, there is a short to correct in that wire. If the fuse is good, you can rebuild the "rear circuit" one device/wire at a time
8) Before connecting any devices or wires inspect them for any damage, wires touching another, or wires touching a metal housing that will create a short.

Note: you can check the current or voltage at any set here as needed to confirm operation. I just wanted to give you a start and then see what happens so I don't write a "book" based on assumptions

Let me know if my assumptions are wrong and how you make out.

Goo luck !

[tvhorman]

Greetings ACDW! Your initial assumptions are accurate!

So let's start at the beginning and take it slow and simple.
Assuming you took apart your system, set your DMM to 20Vdc (or similar range). Measure the voltage at these points:
1) Measure your battery voltage (lest see what your baseline battery voltage is - should be approx 12.6Vdc or better) 12.6 vDC
2) Measure the electrical panel voltage across the Negative & Positive rail 12.6 vDC
These two voltage readings should be the same (approx)
3) Measure the voltage at the hot side of the fuse terminal for the "rear light" circuit that your blowing fuses (black lead on the Negative rail)
This voltage should also be same as the electrical panel voltage in #2 12.6 vDC
If the voltage is good (same) in step #3 , then the wiring to that circuit in the electrical panel is good. YES!!
4) If you got this far, connect a fused load (i.e. a light with an appropriate fuse) between ground and to the hot fuse terminal (that you just measured)
If it works, you know that circuit is working and can proceed step by step to test the remaining parts on that circuit. I pulled the bad wire off the circuit, put in a 5amp fuse, and put a wire direct to the "hot" side of one of the switches, turned on the light and NO BLOWN FUSE!
4b) Set your DMM to DC Amps and connect it in series with your fused load to measure the current and record it in case needed at a later time (easy test while this test load is set up) Didn't need to because of 4)
5) Remove your test load and keep it for later testing
6) Find the first wire in your "rear lights" circuit coming from the electrical panel and make sure it is not connected to a device (so no loads or devices present), insert a 15Amp fuse to see if it blows It did
7) If the fuse blows, there is a short to correct in that wire. Agreed! If the fuse is good, you can rebuild the "rear circuit" one device/wire at a time I plan on this tomorrow!!
8) Before connecting any devices or wires inspect them for any damage, wires touching another, or wires touching a metal housing that will create a short. WILCO!
Thanks for your guidance!!!

[tvhorman]

Howson, I think at this junction I'm going to rewire from the Distribution Panel, one wire at a time and see what happens. I picked up some 14 gauge "outside" multi-strand wire and a few extra fuses to start the process. I will get back when I have more information to share. Thanks for your help!!

[traveldawg]

Folks,
If you're new to this thread (or even if you are not new) it may look a bit more confusing than previously. The OP (tvhorman) had started 2 threads in 2 different forums. Actually I was responding to one and finally realized that there was another (more active) thread in another forum. It can be confusing. So I combined them.

Ted (tvhorman) I sent you a PM just to be sure you saw what I did. No-harm-no-foul. It's just best to keep one thread going for a specific problem.

[howson]

Howson, I think at this junction I'm going to rewire from the Distribution Panel, one wire at a time and see what happens. I picked up some 14 gauge "outside" multi-strand wire and a few extra fuses to start the process. I will get back when I have more information to share. Thanks for your help!!

Thanks for the follow-up. I'm very interested in what you find--if I was closer I'd come over and help!

[ACDW-Ottawa]

Greetings ACDW! Your initial assumptions are accurate!

So let's start at the beginning and take it slow and simple.

7) If the fuse blows, there is a short to correct in that wire. Agreed! If the fuse is good, you can rebuild the "rear circuit" one device/wire at a time I plan on this tomorrow!!

Hi Ted!

Now that I found the active thread, It will be easier to follow It seems like you are now on the right track. I'll continue to follow the thread tomorrow.

good luck

[tvhorman]

Traveldawg, Thanks for the update. Agreed, I'll try to be more careful of that.

[tvhorman]

I would like to thank everyone that participated in this issue. Here's the final results. Yes, there was a wire that was a direct short. Yes, it was ultimately the wire that came from the distribution box however...….the actual wire was the trail end wire that left the final switch pole and disappeared into the unreachable area of the walls! I started rewiring from the distribution box, checking continuity etc. for each connection. It literally came down to the last wire system and I STILL DON"T KNOW WHAT THE WIRE GOES TO OR WHERE IT IS SHORTED!! However, all system lights that I was expecting to work, do! I even left them ALL on with a 5 amp fuse and even after 30 minutes everything still works! I cut the "bad" wire pair, taped them up and made a mental note to location and IF I find anything that's 12vDC that does not work that I will search thinking of that bad wire first. I have attached a picture of the exact wire that troubled me. If anyone can think of what else might be wired in this setup please let me know. Once again, thanks for all your help!

[gbkims]

Ted,
Glad you got it!
Yeah I've still got some wires I don't know where they go or what they do as of yet.