Tail Light Ghost

[Marine-58]

Could use some advice.... Every few weeks my rear tail lights and turn signals stop working due to a blown fuse. Thought that I had found it with a + wire that rubbed through to the frame. Taped it up and was good for a few more weeks. Then the fuse blew again. I have run the wires all the way from the front to each tail light and cannot find any issues.

Hopefully someone has an idea. The only thing I can think of is maybe the fuse block could have an internal intermittent short that only affects this one circuit? Maybe this weekend, re-run all electrical to the rear?

I'm an old fat guy and getting under a vehicle or dash is not as easy as it once was...

[leftybass209]

What condition is the wiring in? When does the problem occur- When braking, signaling, driving, resting? If it's caused by braking, it could be an issue with the brake switch itself. If it's randomly when driving, then you've only fixed one instance of short-to-ground issues, and there are others.

If the wiring is still original, i'd replace it. The brittle well weathered conduit isn't providing much protection, and since there were at least one break in the wiring moisture has probably already worked its way in to corrode the wire/s and increase resistance eventually anyway.

[Marine-58]

The wiring is pretty much a cluster. When I bought this, it was an older rebuild to a hot rod and whoever did the work was not the most conscientious person. From what I have seen, there is some original and some new. The old wires, as I recall are black and green? Should have taken a picture but the new ones where I found the one short are 14 ga red and black.. As to when it happens... Not really sure. As this is an on-going project and I only drive it a couple days a week. Sometimes with headlights on but usually not.

As I'm typing this, dawns on me that maybe there is a connection with the tail lights coming on with the headlights? I'll check that out this evening. Headlights work and never blow a fuse. Before I learned about this forum, spent many hours getting the front wiring straightened out. They had spliced a lot converting to a 1 wire alternator and adding a MSD 6A unit.

[demian5]

Originally Posted by Marine-58

I'm an old fat guy and getting under a vehicle or dash is not as easy as it once was...

You need a grandson to get under there for you.

[Marine-58]

Originally Posted by demian5

You need a grandson to get under there for you.

I wish... None of those yet but we keep hoping...

[Marine-58]

Originally Posted by leftybass209

What condition is the wiring in? When does the problem occur- When braking, signaling, driving, resting? If it's caused by braking, it could be an issue with the brake switch itself. If it's randomly when driving, then you've only fixed one instance of short-to-ground issues, and there are others.

If the wiring is still original, i'd replace it. The brittle well weathered conduit isn't providing much protection, and since there were at least one break in the wiring moisture has probably already worked its way in to corrode the wire/s and increase resistance eventually anyway.

I haven't made it home from work yet but had my son try the lights, turn signal, brakes etc sitting in the driveway and no blown fuse. Not that it proves much other than the issue didn't happen this time. It will probably be this weekend before I can really get under it, but I think you are right, between age and modifications, it is probably best to rerun everything. Even replace the brake switch. Was hoping to not have to get that deep into it, but will be worthwhile when it is done. Taking Friday and Monday off so there will be 5 days to have fun with the truck. Take out the jack-stands, crank up the radio maybe even have a beer or two..

[dmjlambert]

Having a look at the wiring diagram, it looks like the dome light is on the same fuse. Something to think about. There is a connector that goes to the dome light under the carpet below the fuse box, you could disconnect it and see what happens.

[Ol Blue K20]

I've had bad turn signal switches cause blown fuses.

[Marine-58]

I would have never thought of that. The dome light never worked but I thought it was due to no door switch. Thanks for looking that up.

Who would've thought it would be fed from the same fuse...

[Marine-58]

Nothing like reading from a kindle... good suggestion on the turn signal switch also. I haven't checked if the front quits working at the same time.

You guys have good ideas, maybe I won't have to rewire everything?

[Moose Monkey]

Check out any of Vette Vet s posts. Perfect posts with best advice, along with diagrams. He is great.

[Marine-58]

Originally Posted by Moose Monkey

Check out any of Vette Vet s posts. Perfect posts with best advice, along with diagrams. He is great.

All of you guys have given some good advice. Don't take me being slow in answering as being not interested. Working 14+ each day tends to take away from fun stuff. I am taking Friday and Monday off to give me 5 days to work on this + what the wife wants done.

To sum up here is the plan... Starting at the backend, check each taillight and sockets, re-run the wiring back towards the front with all new. Connections will be soldered and heat shrinked. In the cab, will have to rewire for the dome light and the door switches, turn signal switch in the column, not forgetting that the headlight switch also turns this light on. Thinking it will be easier to pull the front seat for this. No telling how the previous yahoo ran everything. The engine compartment was a major pain to clean up.

Tonight after I get home will look at Vette Vet posts... At this point, I'll take advice from anyone...

Thanks again guys, will keep you posted as this progresses...

[Marine-58]

Well.... Not much of an update but here it is. All plans are subject to being screwed up. Originally planned to spend one day doing brakes/shocks on the Vette, swapping it to the driveway and pulling the truck in the garage and start rewiring. I don't know if any of you have worked on the parking brake for a Vette but it is a time consuming pain. Needless to say I spent most of the weekend getting that one going. Ran out of time for the truck. Will get that started this weekend.... I do appreciate everyone's input and will put it to use. Unless the wife comes up with something else...

[ApacheIvan]

My 72 used to blow the taillights due to an exposed wire in the tilt column. It was fine until you tilted the wheel up and it would blow..It has been fixed now, but that was my gremlin.

[Marine-58]

Originally Posted by ApacheIvan

My 72 used to blow the taillights due to an exposed wire in the tilt column. It was fine until you tilted the wheel up and it would blow..It has been fixed now, but that was my gremlin.

I bet that was a tough one to find.... Thanks for the input, it is added to the list of things to rewire. Going to be a busy weekend... Better pick up some more beer...