Fog Light Not Working

I'm having trouble with my driver side fog light. These are the OEM fog lights that came pre-installed on my truck. The driver fog light is working intermittently. The passenger fog light works consistently. I tried replacing the bulb twice, so that doesn't seem to be the problem.

Does anyone have a suggestion for what to try next? Would it be a relay if only one side is working intermittently? Is it most likely the wiring?

I found information on how wiring is run for a 2006, but I'm not sure if this is the same for a 2015. Does anyone have info on this?

 

The wiring diagram for the foglamps on a '15 Taco show them being grounded at points EA and EB, respectively. Check those points, make sure the ground is clean and tight.

 

When I had Mechanics working for me I alway's told them to start where the weather was the roughest on electrical problems.
Unplug the side you are having problems with and turn on the fog lights and take a 12volt test light and see if you have power to the plug coming from the truck to the bulb. If you do then that plug probably has a loose connection or is Dirty. If you do not have power to that side then you probably have a problem with a broken wire or a bad ground. both lights feed off of the same source so if one is working and the other is not then it is most likely a connection problem just my .02.

 

Also check the terminals in the foglamp bulb harness connector, make sure the terminals haven't corroded or been pushed back, or spread apart.

 

Thanks for the help. I just checked the grounds in the parking lot. They seem clean and tight. I will check out the power, connection and terminals when I get home from work.

 

I put a wrench on the grounds and they are tight. The terminals seem clean. The connection seems tight. When i put my meter on the terminals it is reading 6.5 volts. Any thoughts on where to go from here?

 

You need 12 volts to turn a bulb on. You're losing around 6 volts somewhere before it gets to the socket. Trace the wiring carefully, look for and crispy spots or places where the wiring is chafed/rubbing on the frame

 

This ^^^^^^. U might have a Damaged wire that is NOT completely broken somewhere.

 

Simple test is to take your meter and put the positive probe on the lamp connector positive side and the ground probe on your battery negative post with the fogs turned on. If you get 12 volts then you know it’s a ground problem.

 

Thanks guys. I finally got a chance to grab some alligator clips so i could reach the battery and bulb socket. I put the negative on the battery terminal. It initially read 6.40 volts but climbs about 0.01 volts per second. I stopped watching around 7.10 volts. Would this indicate anything?

 

What kind of reading are you getting on the other side? They should match.

 

I just tried the other fog light (passenger side that consistently works. It s reading 11.96 volts.

Or do you mean check the bad fog light while the meter is hooked up to the red post on the battery?

 

You should have the same voltage on both lights. Hook your multi meter up to the bad side and do what the dealer calls a "wiggle test" while the meter is hooked up wiggle the wires and see if the meter reading goes up or down. if it does you have a lose or broken wire.

 

Figured I would contribute.

2015 Tacoma Driver Side Fog Light - not functioning.

On the harness, about a foot up from the connector/plug that connects the actual bulb to the harness, there is a plastic bracket which has a 90 degree bend that is taped to the harness. It is fastened to the body assuming it is there to facilitate a bend in the harness and prevent rub on the body it self.

That is where I found a broken wire, the plastic shroud was brittle and copper wire corroded.

Hope this helps anyone in the future.

 

You do realize that the post was from 2018, right?

 

Yes, every post is date stamped, and the stamp is located on the left of each post.

Hoping to save someone the trouble and headaches, if they happen to read through an old post like I have many times to resolve my issues ...in the future.