Turn signal keeps blowing fuse

[RoadRacer]

ok, I'm 2.5 years into driving I think this is my first electrical problem, but here we are!

I drove through a BIG thunderstorm on Friday night - a lot of rain, so much that you can't see the sides of the road or road markings. Proper texas sized storm. For 30 minutes I was forced to go under 30mph on the freeway. Anyway, the car was wet.

Everything worked, as it always does, my car is very reliable.

Next day I drive and I notice the turn signals didn't work - sure enough a fuse had blown. Hmm.. I change the fuse. It's back to 100+deg and obviously the car is very dry now. The turn signals all work in the garage. I drive down the road and at the first intersection the fuse blows again. Weird?

I've gone through this a few times now. I change the fuse. I test the turn signals, they work. (BTW, the hazards are on a different fuse and ALWAYS work, even when turn signals have blown)

Then I drive the car and they blow.

I'm going to do more testing in the garage, by simulating driving - turning steering, engine running, etc, and see if I can reproduce in the garage..

[JohnK]

I'm not very familiar with the hot rod, but on the roadster it's not uncommon for water to run down the windshield post and onto the fuse box, which is located above the drivers left knee. The flasher cans for hazards and turn signals are mounted on the fuse panel such that they fill up with water and create all sorts of fun. I'm not sure where the fuse panel is on the hot rod, but you may want to start with pulling the flasher can off and seeing if water got in it.

[RoadRacer]

ok, done the tests.. still not found anything.

- I changed the fuse. both signals work fine.
- I turned the steering, no change
- I started the car, no change
- I pushed brake and clutch, no change
- I turned headlights on, no change

I don't think I've missed anything that I do in a normal drive?

Later I'll take it out again and see what else I do to make it blow. I'll go somewhere quiet and drive with the turn signal on so I can tell when it blows..

[RoadRacer]

I'm not very familiar with the hot rod, but on the roadster it's not uncommon for water to run down the windshield post and onto the fuse box, which is located above the drivers left knee. The flasher cans for hazards and turn signals are mounted on the fuse panel such that they fill up with water and create all sorts of fun. I'm not sure where the fuse panel is on the hot rod, but you may want to start with pulling the flasher can off and seeing if water got in it.

Thanks, good idea, I'll pull the flasher, it may be the g-force of cornering that does it..

[33fromSD]

Maybe take a air nozzle and blow air into the fuse box, you may have gotten water into th fuse box that is still damp enough to be causing you issues.

Also, I know Gen2 have sealed LED headlights, how about Gen1, any way water could have gotten into your headlight/signal light or even the tail light?

Jim

[RoadRacer]

Maybe take a air nozzle and blow air into the fuse box, you may have gotten water into th fuse box that is still damp enough to be causing you issues.

Also, I know Gen2 have sealed LED headlights, how about Gen1, any way water could have gotten into your headlight/signal light or even the tail light?

Jim

Possibly, but I can't see any, and the 4-way flashers still work so I think that precludes the lights as a the problem. I do think the flasher unit may have water in.. my next check.

[RoadRacer]

no, the flasher looked clean and dry.. can't make anything fail in the garage.

but you'd think after the 3rd straight day of 100+ anything that was wet isn't anymore. and should either work all of the time or none of the time!

pulling the dash off for a closer inspection..

[Papa]

Not knowing how you connected all your lights, is it possible to unplug them and blow out the connectors with a little compressed air? It sounds like you are getting a short to ground. There could be a bit of water in one of the connectors. Once you blow them out, put a dab of dielectric grease on all the contacts.

[Mastertech5]

I hope you can find it. Intermittent shorts are that hardest kind to find. Pinched wires that one strand might short in certain conditions is one possibility. If you can isolate the circuit you can just run a new wire so you don't have to rip everything apart trying to find it. Good Luck!!!

[33fromSD]

no, the flasher looked clean and dry.. can't make anything fail in the garage.

but you'd think after the 3rd straight day of 100+ anything that was wet isn't anymore. and should either work all of the time or none of the time!

pulling the dash off for a closer inspection..

Water is a fickle beast. You would think after three days of 100 degree weather it would be dry but take a clear 16 oz water bottle and empty it out and put the lid back on and let is sit for 3 days, you'd be surprised that there is almost more water in it then. The problem with the weather by you in Texas (and me in SoDak) is not only the water from the rain but also the high humidity from the temps. A lot of moisture in the air.

Jim

[RoadRacer]

Not knowing how you connected all your lights, is it possible to unplug them and blow out the connectors with a little compressed air? It sounds like you are getting a short to ground. There could be a bit of water in one of the connectors. Once you blow them out, put a dab of dielectric grease on all the contacts.

Yeah the short to ground is confusing. There's no connector, my lights are 'hard wired' with soldered joints, and heat-shrink tubing, and flex tube over all that - and tie wraps everywhere to stop movement. I was kinda paranoid when initially putting it together to stop this kind of weirdness. I wanted very high reliability from the wiring.

But ultimately that's pretty hard of course, without a custom harness and MIL SPEC connectors. And my car is a pretty harsh environment - stiffly sprung, driven hard, and zero weather proofing

When I find it, we'll all understand it

[RoadRacer]

Narrowing it down! After inspecting behind dash, fuse panel etc.. I took for a very closely monitored drive. Driving straight with both indicators was fine.. then I turned left. Immediately a very faint pop and the turn signals went out. So now I know a little more

[Mastertech5]

Do you have the Ididit column with its own column connector? If so check the flat harness coming out of it for chafes at the column supports they have sharp edges. Does it only blow when you have a turn signal light on? If so it's on the lamp side of the circuit, if not it's on the feed side to the turn signal switch.

[RoadRacer]

Do you have the Ididit column with its own column connector? If so check the flat harness coming out of it for chafes at the column supports they have sharp edges. Does it only blow when you have a turn signal light on? If so it's on the lamp side of the circuit, if not it's on the feed side to the turn signal switch.

Yeah, I'm down about 8 fuses so far, luckily I have a big box

It's down to the column or cable I think, so I'll take out the column and inspect the cable thoroughly, and then see if I can repro the short with a multimeter on ground and each pin in turn.

[Mastertech5]

Didn't this start happening after you relocated your steering column? That should be a red flag. It seems like your on the right track!

[RoadRacer]

Didn't this start happening after you relocated your steering column? That should be a red flag. It seems like your on the right track!

No, interestingly it happened 2 days before. so, it could be related or not!!

[RoadRacer]

ok, this is fun. I feel like a detective!

I noticed that it only happens on the left signal.

I disconnected the column connector, and tested that none of the 4 turn signal wires went to ground when signaling, and that there was continuity between the 12v feed and all 4 signals. So it wasn't the column at all. (but see later)

Then I used a wire to connect the signal feed to each of the signal wires on the dash loom side. Each signal came on in turn, but I kept trying and one time the fuse blew when testing the front left.

So I focussed on the front left. I plugged the column back in and set it signaling left - luckily it worked (it's about 50/50 if it blows) - so I started working my way along the loom, wiggling it to see if I could find a weak link. All the way up to the headlight, it's still flashing! I wiggled the wires going into the headlight - still working! I took the headlight out.. looks perfect, no water, no chaffing.

Of course, short of unwrapping the loom, there's not much more to do, so it's become a weekend task to dig deeper.

And this morning I woke up and realized that any of those steps could have shown up the issue, because it's sporadic. Just because they didn't fail this time, doesn't mean they arent the problem LOL

[33fromSD]

It would be a pain cause you said there isn't a connector just a soldered connection, but you could try running a temporary wire (get a 16 Awg spool) from the left signal light (you'd have to cut the existing connection) on the outside the car to the connector in the steering column (strip the end by the column connector and slide it in to the back of the connector just enough to make contact). Tape it down in a few spots so it's not flopping around and run it around the block a few times.

This would tell you if its in the wiring harness to the left signal light. if that works, then just run that wire along the exiting wire harness and make it permanent.

Just a thought.

Jim

[RoadRacer]

It would be a pain cause you said there isn't a connector just a soldered connection, but you could try running a temporary wire (get a 16 Awg spool) from the left signal light (you'd have to cut the existing connection) on the outside the car to the connector in the steering column (strip the end by the column connector and slide it in to the back of the connector just enough to make contact). Tape it down in a few spots so it's not flopping around and run it around the block a few times.

This would tell you if its in the wiring harness to the left signal light. if that works, then just run that wire along the exiting wire harness and make it permanent.

Just a thought.

Jim

Yeah. It's such a pain when things don't ALWAYS fail. Just whenever they feel like it. LOL

[Mastertech5]

Did you find the short yet?

[RoadRacer]

Did you find the short yet?

No, racing on Saturday so had to abandon the search to work on steering and alignment and some other wiring.

[narly1]

I hope you can find it. Intermittent shorts are that hardest kind to find. Pinched wires that one strand might short in certain conditions is one possibility. If you can isolate the circuit you can just run a new wire so you don't have to rip everything apart trying to find it. Good Luck!!!

I'm with you on this being the culprit. The best one would probably be able to do is isolate the short to only one corner of the car. One would do this by disconnecting the power running out to the lights, one corner at a time.

Earl

[RoadRacer]

I'm with you on this being the culprit. The best one would probably be able to do is isolate the short to only one corner of the car. One would do this by disconnecting the power running out to the lights, one corner at a time.

Earl

Yeah, I'm pretty sure I know the corner. D/S front. I could for sure run a new wire and be done, but I am VERY curious how/where it happened. As I said, I thought I was very careful with wiring, so I want to know where I screwed up!

[narly1]

Yeah, I'm pretty sure I know the corner. D/S front. I could for sure run a new wire and be done, but I am VERY curious how/where it happened. As I said, I thought I was very careful with wiring, so I want to know where I screwed up!

My experience has been that:

1. Places where the wire turns around a corner or passes though something (thus rubbing against metalwork)

or

2. 1or 2 errant wire strands poking out from the back of a connector or underneath tape/heatshrink at a connection/splice

are good places to start.

In cases like this a sharp eye looking for the above + any slices/breaks in the wire insulation is your best troubleshooting tool. Make sure to look "behind" the side of the wire that you can easily see. Trouble hides in the dark, LOL.

Earl

[Dgc333]

If you are using the Ron Francis wiring harness there are wires to hook up a toggle switch for the directions too. Check those wires too.

[RoadRacer]

My experience has been that:

1. Places where the wire turns around a corner or passes though something (thus rubbing against metalwork)

or

2. 1or 2 errant wire strands poking out from the back of a connector or underneath tape/heatshrink at a connection/splice

are good places to start.

In cases like this a sharp eye looking for the above + any slices/breaks in the wire insulation is your best troubleshooting tool. Make sure to look "behind" the side of the wire that you can easily see. Trouble hides in the dark, LOL.

Earl

Yep. Love the "trouble hides in the dark"!!

I have at least 2" of heat shrink over every connection so I'm thinking it's going to be the former.. those grommets always seemed a bit unreliable to me. I found one grommet in the trunk going to the plate light (unrelated to this) that had come out of the hole, and moved up the wire so that could so easily have rubbed through. It was fine, but..

Now you have me wanting to go out there... NO! Sunday..

[narly1]

Yep. Love the "trouble hides in the dark"!!

I have at least 2" of heat shrink over every connection so I'm thinking it's going to be the former.. those grommets always seemed a bit unreliable to me. I found one grommet in the trunk going to the plate light (unrelated to this) that had come out of the hole, and moved up the wire so that could so easily have rubbed through. It was fine, but..

Now you have me wanting to go out there... NO! Sunday..

“When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.”
― Arthur Conan Doyle, The Case-Book of Sherlock Holmes

[peterh226]

Make sure you have disconnected the right wire in the harness to the steering wheel. There were a couple in that harness that caused me some grief (but I cant remember which ones right now).