05 Tacoma keeps eating Low Beams. Diagnosis Help

What should I be looking for then @Jimmyh ?

 

Other than what is covered already; I would suggest going back to OEM Bulbs. And check for loose connection as a flickering bulb will not last very long.

 

I'm sooooooo glad brain farts don't smell... Is there a face palm smiley?
Thanks for correcting me.

 

If the corrosion (i.e. additional resistance) is on the headlight socket heat will be produced at that point. The heat has to go somewhere and some of it will dissipate to the bulb filament. Add that to the heat the bulb filament produces when it’s on and the filament becomes thermally overstressed and opens like an fuse. That’s my best explanation for this.

 

V=I/R or
I = VR: Voltage applied to the circuit stays the same, if the Resistance increases with corrosion then the current increases.

Other thing to look at is replacing the Relay, I'd do this before you start messing with the wiring harness.

1) clean all corrosion off harness at bulbs and relay connnectors. There is a nice electronic/electric spray cleaner you can buy for this.
2) add dielectric grease to connectors.
3) Replace relays if still blowing bulbs.

 

We all do it. Sooner or later.

 

We all do it. Sooner or later.

You need to have another look at Ohms Law.

V = I/R and I = VR are both incorrect.

V = I/R should be E = I x R or Voltage = Current multiplied by Resistance.


I = VR should be I = E / R or Current equals Voltage divided by Resistance.

If circuit resistance increases then the circuit current decreases

 

You mean add dieltric grease to seal, not connections, right?

 

Yes you are correct

 

Make sure you change the bulbs as a set and not just 1, I have seen that cause issues in the past when a customer only changed the 1 bulb because the other bulb was still "good".

 

So what did you find?

 

I removed both low beams and checked the voltage at each with a DMM in MIN/MAX with the engine running for 5 minutes on each side. Voltage read the same at both harnesses (+- like 0.1 volts). Noticed corrosion at the driver's side harness. Cut the drivers side harness, soldered in another harness, shrink wrapped the connections. Also cleaned grounds and sanded them with sand paper to polish them. Replaced both headlights with the cheapest sylvania's (longest bulb life) and wore gloves when replacing the bulbs. Time will tell if this fix is permanent. Thanks to all for the responses

 

Awesome, I'll await feedback on the results. Thanks for posting