Headlight Dimming Issue

Going to try and explain without being to confusing. I bought a ‘13 Tacoma SR5 recently and put new LED bulbs in after purchase since old ones burnt out. Ive always had this issue with the truck, but recently it’s been getting worse and I have to wait longer to turn on lights. when I flip on my headlights they won’t come on unless I turn off my fog lights, then I have to let them sit for about 15-20 seconds then I can turn my fog lights on. If I try any sooner the headlights just shut off. I figured the LEDs might be drawing to much power so I switched back to standard halogen bulbs thinking that would fix the issue. No luck, halogen bulbs won’t even turn on at all. It has to be a wiring issue I’m sure, but hate electrical issues and just for Toyota to diagnose the issue they want $150. Any help or answers would be great, not sure if anyone else has experienced this issue. (Pictures show both sets of headlights bulbs and the wiring harness that looks factory and one that looks like it was put in after for some reason)

 

The female end of the connectors are worn (loose) try dielectric grease or replace them.

 

Disagree. Dielectric grease will not help loose connections and is not a conductor of current.

Check the voltage at the connection when you turn it on does it have 12 Volts between the Hot wires for High and Low beam and the White Wire with a Black Strip?

Yes - It is not a wiring problem.

No - It is a wiring problem.

 

And get rid of that shitty ass splice job.

 

I do plan on fixing the splice job and doing it right but alright I’ll give that a check when I’m off work, let’s say it isn’t a wiring issue, what would cause the halogens to not work, but LEDs work somewhat?

 

Probably because LEDs draw less current than halogens. You might have enough current to light an LED, but not a halogen. You need to get a DVM and do some testing.

BTW: I'll resist the urge to chide you for using LEDs in a housing designed for halogens.

 

I think you did....

 

Was that splice job just to get the LED bulbs in or for something else? Did you have the dimming issue before the LED install(you said you always had this issue)?

 

So I bought the truck from a used lot (bad idea I know) and one bulb wouldn’t turn on at all with LEDs cause the genius who had it before wired it wrong, took it to Toyota and they “fixed” the issue for a few weeks and now they barely come on and won’t turn on with the fog lights on unless I turn them off and then back on.

And the wiring was like that when I bought the truck.

 

OP, have you thought about bypassing the headlight connector and wiring?...

 

Have you checked the ground? Try taking a spare wire (18ga or so) that is stripped at the end, twisted tightly or soldered, try to put (wedge it against the bare terminal) it in the back side of the connector in the ground terminal and clamp the other end of it to a solid ground on either the engine block or back to the battery ground.

Chase the wires back and look for any pinched areas or chaffing.

Check the fuse and relay for corrosion and solid connection as well. Also try swapping the relay for another to see if that works, sometimes the internals of the relay get gummed up or corroded.

 

If your headlights are dim and the previous ones burnt out real quick I would attribute that to a bad ground. Probably would not be a bad idea to run an independent ground to the body, or if.you want to get real serious run a dedicated ground to the battery. See if it helps.

If you want to try out the bad ground theory, you can always try boosting the current ground that is there using a power probe or even just using an alligator clip strapped to battery negative and touch the lead from that to the ground at the headlight. It's a quick and non invasive test that works. If the bulb gets substantially brighter, you found your winner.