Passenger side turn signal dim compared to driver side

[tadkingnkc]

So I changed everything exterior back to incandescent and thought I solved all the worlds problems. Everything lit up and functioned As expected. But upon closer inspection, I regret putting it all back together because my RF turn signal under the headlamp is half the brightness of the driver side. It’s illuminated but way more dim and way more noticeable. Could this be a bulb issue or will I get the standard “you gotta ground issue” response based on my research? Would a ground issue cause a partial illumination? Maybe it’s a bad bulb? Wishing I had noticed before putting it all back together. Dang the luck. Thanks for your responses, knowledge, and expertise!

 

[CRM]

Interesting. I just noticed a few days ago that mine is the same as yours. I'll be following the thread.

 

[WP29P4A]

If the bulb lights up, it is not the problem. Something else is reducing the voltage TO the bulb. The only way to find the problem is to carefully inspect and test the light circuit, one piece at a time. The clues you are looking for are, bad connections, bad sockets, wrong type of bulb in socket, bad or missing grounds, oxidized wire, etc. If the inside of the socket has two connections and the bulb only has one connection on the bottom, that is a problem. Trailer wiring/plugs are also common causes.

Compare the side that works to the side that has the issue, if you switch bulbs does the problem move? If you want to test for a bad ground, use your test light or meter to determine which wire on the signal light with the issue is the positive. Take a piece of wire with the ends striped back or alligator clips would be better, touch one end to ground and the other to the ground terminal on the signal light. If it gets brighter, you have a ground issue, if it doesn't you have an issue on the positive side.

 

[Scott91370]

Is the bulb a dual filament (blinker/parking)? If so it is very possible it's tunred 180* out of phase making the parking filament flash.

 

[75gmck25]

Assuming the bulb is inserted correctly, you have a poor ground connection somewhere and it’s acting as a resistor instead of a ground. Since it’s only one light that has issues, it’s probably the ground wire for that front light housing or for the side marker housing. On my truck those two lights alternate flashing, so they are interconnected. Just take each ground screw out, use some sandpaper to clean the area behind it down to bare metal, and screw it back in.

 

[WP29P4A]

Is the bulb a dual filament (blinker/parking)? If so it is very possible it's tunred 180* out of phase making the parking filament flash.

How do you install the bulb out of phase when it has two lugs at different heights to keep you from installing it backwards?

Could be wired out of phase if it was replaced?

 

[Radiohead]

By cramming it in, not realizing that there is a difference?

If this lamp is near the battery, check for acid corrosion around the ground lug too.

 

[Scott91370]

How do you install the bulb out of phase when it has two lugs at different heights to keep you from installing it backwards?

Could be wired out of phase if it was replaced?

By cramming it in, not realizing that there is a difference?

If this lamp is near the battery, check for acid corrosion around the ground lug too.

Bingo... I've seen it several times. And as old as these trucks are the metal sockets are only getting weaker.