Marker/running light issue (Bricknose)

[chillman88]

Okay all, this one has me royally stumped.

I got to work today and noticed my running lights weren't working. My first thought was maybe I ran a screw into the cab light harness mounting my CB under the roof.

I checked the fuse, it's fine. I tried a multi-meter on the CB screws and there's 0.01v with the lights on (kinda, i'll explain)

Removing the screws made NO difference...

I assumed it must be the switch, headlights were fine but no running lights. Swapped out the switch... with two different ones. SAME symptoms.

Turns out if I set the switch JUST between the two positions the running lights AND headlights will stay on. My headlights ARE on a relay setup which has been absolutely flawless and I don't expect that to be the issue but figured i'd mention it.

What the hey is going on? Can anyone point me where to look? I kinda need to get this fixed before I get a ticket....

 

[saburai]

Watching(and thinking)

 

[IDIBRONCO]

It may or may not be the same, but on a bull nose, there's a fuse that will cause you to only have headlights and brakelights if it's blown. No running/tail lights. Also the dash lights won't work. It may be worth a try to check the fuses.

 

[Thewespaul]

Something else to check is the pigtail for the headlight switch, you may have a burnt wire that’s not allowing power to go to your running lights

 

[chillman88]

I'm going to have to dig out a wiring diagram I guess. I'm hoping to try bypassing half the circuit by feeding the fuse terminal power just to see if they come on by that. That'll tell me if the issue is "upstream" from the fuse.

Really what I need to do is drop the dash and swap my other harness in, but it's from a gasser and I don't have time to screw with that before the rally. Does anyone know if the wiring for the running lights goes through the turn signal switch in the column at all?

It may or may not be the same, but on a bull nose, there's a fuse that will cause you to only have headlights and brakelights if it's blown. No running/tail lights. Also the dash lights won't work. It may be worth a try to check the fuses.

That should be fuse #4 which is labelled something along the lines of "Marker Lights/Illumination" and it appears to be fine. I'll have to pull it out with pliers tonight as I couldn't get it out with my hands. Looking at it it LOOKS like it's not blown. Besides, they work with the switch jammed halfway???

Something else to check is the pigtail for the headlight switch, you may have a burnt wire that’s not allowing power to go to your running lights

Pigtail had been replaced at some point. When swapping the switches during testing I wiggled all the wires and their splice joints and nothing seemed to make any difference either way. If I jammed the switch so they were on they wouldn't go out wiggling the wires. If I put the switch where it belongs they didn't come on wiggling them either. Very puzzling.

 

[chillman88]

Well I'd rather be happy and an idiot than not fess up. Replacing the fuse worked for now but the real question is why did I blow a 25amp fuse in a 15amp circuit. We'll see how long this fuse holds up.

 

[chillman88]

Worked all the way the drive in to work. I'm gonna chalk it up to the heat and frustration that stacked up yesterday. I'll update if/when I find whatever blew the fuse. The more I think about it I have a suspicion that it might be my trailer.

Thanks for trying to help guys.

 

[nostrokes]

Just an idea for ya to look at too.. mine did the same thing I found a wire on my stereo (pioneer aftermarket) that is for lights on a amp ( I think) it was shorting out to the dash everytime I set the e brake.. may not be your issue too but it's something to look at if you have a aftermarket stereo..

 

[chillman88]

Just an idea for ya to look at too.. mine did the same thing I found a wire on my stereo (pioneer aftermarket) that is for lights on a amp ( I think) it was shorting out to the dash everytime I set the e brake.. may not be your issue too but it's something to look at if you have a aftermarket stereo..

That'd be worth looking at. I taped up the wires good when I put it in but it could have chafed or something.

 

[IDIBRONCO]

Just an idea for ya to look at too.. mine did the same thing I found a wire on my stereo (pioneer aftermarket) that is for lights on a amp ( I think) it was shorting out to the dash everytime I set the e brake.. may not be your issue too but it's something to look at if you have a aftermarket stereo..

Not light related, but I once had a Kenwood short out in my first 85 F250 diesel. I was leaving work and the radio started to have a lot of static. I stopped at the edge of the parking lot and saw that smoke was coming out from around the radio. I threw it in reverse, dumped the clutch and gave 'er hell. It died just as I got into a parking spot. I disconnected all of the wires and then found out that there was no power inside. I had to get towed home. I couldn't see any burned wires anywhere. While I was moving the wires under the hood, I found a wire close to the alternator (I'm thinking a fusible link) that while it wasn't burned in two, it had a weak spot in the insulation. I cut the insulation and the wire strands were burned in two right there. I reconnected them and had power back inside the cab so I repaired the wire. At this point, I found out that it STILL wouldn't start. I finally tried the power wire to the FSS. It had power with the key on, but the FSS wasn't working. I switched the top of the pump out with another one I had laying around and it started up like usual. To this day, I have no idea how a shorted out radio could take out a FSS (the engine was running when it shorted). I now always install an aftermarket fuse on both the power and ground wires when installing a radio.

 

[FoolhardyIDI]

If it is the dually then there is a relay next to the washer fluid reservoir. I had my running lights give me trouble a few years back turned out to be that relay.

 

[nostrokes]

If it is the dually then there is a relay next to the washer fluid reservoir. I had my running lights give me trouble a few years back turned out to be that relay.

Mine also has that relay. It's for the trailer lights on mine but it wasn't affecting the truck lights because when I rewired the trailer plug it wasn't working. Found a shorted fuseable link next to the passenger battery...

Man I hate electrical!!

 

[chillman88]

So I'm pretty good at having a problem disappear and forgetting about it until it rears it's ugly head again. Pretty sure I finally nailed this one.

I was getting ready to head home, with a trailer, after dark, when I noticed I didn't have any gauge lights. Looking around I noticed my marker lights were out too. Remembering this problem I tried a new fuse. Instantly blown.

After getting to a parking lot and tracing several different things, and sacrificing several fuses to the electrical gods I managed to find this abomination...

You must be registered for see images attach

You must be registered for see images attach

It was hanging down grounding on the hitch. Some mess the PO left me. Pulled off the wire nut up top and taped it up real good. Hopefully problem solved now!

 

[MtnHaul]

Gotta' love someone who uses wire nuts on a vehicle! I don't even like using them when I connect sprinkler valves.