Passenger Side Low beam Headlight Shorting out.

Looking for a sense of direction on a very annoying issue, I have an 06' Tacoma with a headlight with the mind of it's own! I noticed a while ago after going through some deep puddles that my passenger side low beam likes to flicker on and off or work intermittently.

I have swapped bulbs from the drivers side and I'm left with the same result, I went under the hood to check for any physical damage on the wires, loose grounds, blown fuses etc.. but everything seems to be as it should. I recently hooked up a multi meter to the fuse box and get a consistent 12V from where the fuse is for the passenger low beam but when I connect it directly to the H4 style plug the voltage seems to jump around a bit.

I am curious if anyone has come across a similar issue with their truck and if I should start by replacing the H4 plug with a new one to see if it fixes the issue? Keep in mind I have gone over the plug with a soft brush and contact cleaner but didn't seem to work, the outside of the plug looks as if it has over heated at some point as the plastic housing looks burnt. Any insight is much appreciated, cheers.

 

Since your voltage checks out and the initial visual inspection looks fine, I think you’re on the right track, especially considering the plug looks burnt. My guess would be there’s some corrosion or a poor connection inside the connector where the wire is crimped to the pin.

H4 pigtails are really cheap on eBay, and your local parts store might even have them in stock. If you want to be 100% sure, you can always bypass the connector with some jumper wires. Unfortunately, I don’t have a wiring diagram to reference.

 

Sounds like a good excuse to upgrade the headlight harness.

https://www.tacomaworld.com/threads/the-ultimate-headlight-upgrade-h4-not-led-or-hid.398066/

 

Get some CRC dielectric grease and grease it. This will help with the connection and with rattling.

I had a few vehicles with "burned out bulbs". . .used grease and worked perfect for many more years

 

Okay yeah now that I have had some time to look into things further I've learned that these trucks run a negative wiring system for the headlights and that an upgraded harness can fix a lot of issues when converting to LEDs or headlight upgrades. I've taken a look at some other possible scenarios to see if I can come up with anything that could cause my issue but everything seems to be in working order, do you think from experience that if I pull the trigger on a harness upgrade than this will put this problem to rest? Thanks

 

I only have limited knowledge on the subject, but this harness is technically replacing the facroty stuff, and getting power directly from the battery, so assuming your problem is not jsut a bulb it would make sense to try it. Also, you will get better light output than stock.

The forum member who started that psot I linked is still active, and responsive. Maybe try asking your question in that thread, and ask him if he thinks this upgrade would solve your issue. He may be able to point you in the right direction. Good luck!

 

Much appreciated! Thank you