One blinker not working
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From: Denver Metro Area, CO
No, they are not the same; the one on the back of the fusebox (sandwiched between the fusebox & firewall) is for the emergency flashers; the opposing one (front, where all the fuses are installed) is for the turn signals. They are different in that they have different electrical capacities.
But those devices are not your problem, changing them will fix nothing. If one side of the vehicle flashes normally, then the flasher device is working correctly and you need to search elsewhere to find why the other half of the vehicle doesn't flash - bad ground in the back as was suggested is a good place to look IMO. Some (most?) of these trucks have factory grounds at each tail light. There may also be a separate ground for the license plate illumination lamps.
And there's no telling what your wiring is like if you have an owner-added trailer harness back there....
But those devices are not your problem, changing them will fix nothing. If one side of the vehicle flashes normally, then the flasher device is working correctly and you need to search elsewhere to find why the other half of the vehicle doesn't flash - bad ground in the back as was suggested is a good place to look IMO. Some (most?) of these trucks have factory grounds at each tail light. There may also be a separate ground for the license plate illumination lamps.
And there's no telling what your wiring is like if you have an owner-added trailer harness back there....
Fleet Mechanic
Joined: Jul 2003
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From: Atlantic Canada
This should be true, but, as I posted above, my left side flasher was not working, and replacing the flasher relay fixed it.
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Ok so I looked over the whole truck were the wiring would go to the lights and I found a section of the ground wire coming off the side light on the driver side is frayed near the socket. The side light socket has three wires coming off it two brown and 1 black (ground) but one brown goes towards the fire wall the other brown goes directly to the turn signal so that can possibly be where the system is shorting out and causing the blinker not to work?
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From: Virginia
If you re-read your post, you said both sides were messing up. I know strange things happen sometimes, but that rule should hold true 99% of the time.
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From: Virginia
My problem is that the driver blinker will not work. I originally thought it was a bad bulb so I changed that along with the socket. Then I tried replacing the fuse and it still wouldn't work. To make the situation even more weird the passenger side works but when I turn the day lights on the driver side works but the passenger side doesn't come on. I was hoping y'all can share some insight and different things to try to get them back working properly. Any suggestions are welcomed and thank y'all!
If it is the front lights, when you turn the markers or headlights on, both sides marker lights work correct?
When you turn the marker lights on, the pass side front bulb stops blinking?
If I got it right so far, try this experiment; Twist the bulb and socket out of the pass side and let it hang there. Get a scrap piece of wire, hook one end of it to the battery negative post. Strip the other end to bare copper about a inch long.
Get the blinkers going on the pass side, and then turn the markers on so it goes out. Leave it that way, take that scrap piece of wire that is hooked to the battery negative, and stuff it down beside the bulb so it touches the brass part of the bulb while the bulb is still plugged in to the socket. If the bulb starts blinking, you know it's a ground problem at that bulb.
Fleet Mechanic
Joined: Jul 2003
Posts: 1,844
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From: Atlantic Canada
Don't worry, I understand electrical and that it is a single flasher for both sides and one shouldn't work without the other, but my main point was really that in diagnosing a problem with the system on a 35 year old truck, why not just install a new flasher relay for the heck of it.
Mine may show up as a different problem later on, but for now, a cheap flasher fixed the problem.
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Yes sir I am but I was doing what a previous posted stated about checking the ground wiring to the back to make sure that the connections were good. While I was doing it I was going to check as much as the wires I could to see if it's loosing connection somewhere else. The side markers don't work at all at the moment, and the side markers connect directly to the turn signals with one wire the other goes to power and then the third is the ground and that is the one that has an exposed section before it grounds out so im gonna try your experiment to check the grounding. I wasn't to concerned about the side marker lights not working at the moment but can those not working effect the turn signal lights from not working?
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From: Virginia
No, the side markers are a different circuit(brown). There is a brown wire running all over the truck from front to back that runs all the marker lights. That's why there are two browns at the light you are looking at, the brown circuit is feeding that light and then continuing on to feed the front lights. You will notice both front turn/marker lights have a brown wire running to them.
But both circuits (brown marker and the turn circuits) do use a common ground from the bulb. That is why turning the marker lights on can mess up the turn lights, because of the common ground that can go bad.
But both circuits (brown marker and the turn circuits) do use a common ground from the bulb. That is why turning the marker lights on can mess up the turn lights, because of the common ground that can go bad.
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Ok thank you for clearing that up! I was starting to get confused when I found that and my bad for making it sound like I was trying to fix something else than the original post. But im going to try that experiment tomorrow and see if that ground seems to be the problem. Thank yall again for yalls advice! It is much appreciated!
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