Fuse and/or Relay Locations for Day Time Running Lights, Main Headlights, & Turn Signals???

[TacoMoFo]

I hope someone here can help. I'm starting to have serious problems with my aftermarket Alpharex headlights after 10 months with no issues. Depending on whether I have my lights set to auto or manual the passenger side headlight will either be completely on (DRL + main beams) or completely off. Turn signals still work no matter what. Also, the high beams only turn on for the passenger side now. To me this indicates that something is wrong with the DRL and/or main beam circuit paths. The Alpharex lights themselves all turn on so only the switching logic is affected. My first troubleshooting step is to check the DRL and main headlight fuses (or relays) but I can't locate these. I have searched the 3 fuse boxes (left engine, right engine, glove box) and can't find anything related to the front headlights. I have also searched the internet for the locations of these items but I can't find anything. Does anyone know the fuse and/or relay locations that control the DRL and main beam head lights? Also, where is the turn signal fuse/relay???

One more thing. The driver side headlight "flickers" sometimes when driving. I think this suggests a faulty relay but I'm open to other ideas.

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[dvrgz]

Damn. This sucks to see. I have a set too. No problems so far. Have you reached out to AlphaRex? I had some questions during my install. They were pretty helpful/knowledgable

 

[TacoMoFo]

Damn. This sucks to see. I have a set too. No problems so far. Have you reached out to AlphaRex? I had some questions during my install. They were pretty helpful/knowledgable

As I mentioned in my post, I don't think it's the alpharex headlights themselves that are the problem. It's gotta be a light switching control issue since I can get all the alpharex lights to turn on for different headlight setting on the steering wheel. However, I probably will reach out to them anyways to see if they can point me in the right direction. Too bad I have to wait until Monday...

 

[dvrgz]

As I mentioned in my post, I don't think it's the alpharex headlights themselves that are the problem. It's gotta be a light switching control issue since I can get all the alpharex lights to turn on for different headlight setting on the steering wheel. However, I probably will reach out to them anyways to see if they can point me in the right direction. Too bad I have to wait until Monday...

Right. I’m not saying this is an Alpharex issue, but I’m sure they can offer you some insight. They were knowledgable in all aspects related to lighting when I spoke to them.

I see you’re from the Los Angeles area also. I picked my lights up from HQ directly (Irwindale). They offered me to bring my truck to them if I had any problems and they’d check it out

 

[Sner]

Chances are it’s with the Alpharex headlamps. Aftermarket parts + oddball issues are always place to start. While Alpharex is known to be a good quality, instead of chasing oddball parts not normally an issue, first thing to do is reset everything back to OE, and diagnose from there. You’re not likely to like what I am saying, but it’s the fact.

 

[VBFD Taco]

No idea how to help out but curious how this turns out. I too have AlphaRex and hope this is gets figured out, just in case.

 

[TacoMoFo]

Chances are it’s with the Alpharex headlamps. Aftermarket parts + oddball issues are always place to start. While Alpharex is known to be a good quality, instead of chasing oddball parts not normally an issue, first thing to do is reset everything back to OE, and diagnose from there. You’re not likely to like what I am saying, but it’s the fact.

I agree with you and I wish I could revert back to OEM but I sold the original headlights that came with the truck around the time I installed the Alpharex. Sigh...

 

[TacoMoFo]

UPDATE: It's been raining hard in LA the last week and I noticed my driver side headlight had moisture inside the glass cover. I removed the headlight and opened the cover with the PCB and several drops of water came out. I don't see any short or obvious damage but maybe there is??? However this is not the headlight with the main issue. The passenger side is the one not turning on. I've taken video of several scenarios (lights swapped, lights swapped one at a time, lights not swapped, lights not swapped one at a time) and I will be showing this to Alpharex on Monday. The scariest thing I have discovered is that the driver side relay intermittently turns the high beams on/off and you can actually hear the uncontrollable switching for several seconds before it stops. Could this be from the water that got in??? I want to capture this on video but its only happened twice and I didn't have my phone ready to take video.

Until this whole issue gets resolved I will not be driving at night.

 

[TacoMoFo]

UPDATE #2: I think I figured out the problem. I removed the driver side PCB board to see what was on the other side and it turns out a second PCB is right underneath and it was water damaged. See below pics. Not sure you can see in the photo but a few components were growing "rust fuzz" to other nearby components which I suspect were causing shorts. This might explain why my DRL lights were flickering as I drove or why the relay inside the headlight would spontaneously switch on/off multiple times on its own. I also noticed what appears to be burn marks on a few components but I can't tell for sure since everything on that board is so tiny. I cleaned the board with alcohol and Qtips (like the techs at my job do) and reconnected/repackaged everything for placement back onto my truck. For completeness, I also took a look at the PCBs on the passenger headlight and they were perfectly clean. No water damage whatsoever.

The bad news: The driver side headlight no longer works except for the turn signal. My cleaning must have done something to the PCB or I didn't reconnect the cables right.

The good news: The passenger side is now fully functional just like before. Somehow the short(s) on the driver side PCB affected the behavior of the passenger side which is why it behaved so weird these last few days. I now feel comfortable driving around town later tonight because I have one functional light and both of my turn signals.

I plan to drive to Alpharex on Monday to pick up a new PCB replacement. I also want to know how water got into my headlight. This last piece is really important because this incident will probably happen again if the entry point can't be plugged.

I hope all of my headlight drama helps someone. In the meantime, I still want to know... Where are the fuses for the headlights located. Anyone??? Even Toyota doesn't know. I went there this morning and the master tech didn't know.

 

[VBFD Taco]

I know you figured out the issue but for future problems, check this site out. StartMyCar
Found out about it from ONEZ ST on the 4th gen Tacoma forum. Good for finding out where the fuses are. Click on the Toyota emblem and go from there.

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