Proper headlight upgrade

What is the headlight circuit fuse rating on the first gen? I wouldn't recommend it, but even if it were possible, you will get noticeably better results running a standalone harness.

 

The stock fuse is 10A per bulb so it will survive but there are no relays between switches by the steering wheel and bulbs, so at 90W per bulb you would be running 15A through the switch. It might not like it on the long run. Wires are designed to not fry at 20A at the steering wheel (or 10A at the bulb) but I would be more worried about any connector rather than wire. The highest resistance is always at connectors and switches, and these are places that would heat up.

This is actually the main reason why I swapped all my bulbs (besides H4 in headlights) to LED. Four stock blinkers alone are pushing up to 8A through the flasher circuit, while all four LED take 1.6A

 

Just ordered the ultimate headlight upgrade with negative switching harness and H4 bulbs from SMS for my '04 Tacoma double cab. I'm sure the instructions will explain, but I'm curious about a few things. Do the trigger wires to the relays (stock headlight power wires) run next to the battery where the relays are mounted? I assume you cut the stock harness near that area and crimp those wires to the relay trigger harness wire.

Secondly, are people removing the remainder of the stock harness from where you cut the trigger wires out to the headlights, or leaving it? I would remove it unless it is needed for something else, like parking lights and the new harness didn't have this. I'd like to look at a wiring diagram for the SMS harness upgrade, but don't see one on their website.

Thanks

 

There is no cutting of any sort, the upgrade is entirely plug and play. Plug the new harness into the driver side headlight factory plug, this will go to the harness relay, and connect the negative and positive terminals to the battery. Then plug the bulbs in the new harness connectors and that is it. There is nothing to remove, cut or crimp.

 

Wow, I never imagined it would have been that simple! So the driver side headlight factory plug goes to the new harness; does the passenger side also plug into the new harness to trigger the other relay, or does the driver side factory plug trigger both relays? If only the driver side factory plug is used, does the passenger factory plug just hang there?

Thanks for the info!

 

Correct on all accounts, it is super simple. I was unwilling to design a headlight upgrade that required any permanent modification. The driver side plug triggers the relay for both sides. Some people optionally tape over the unused passenger plug, but it is not required, so yes it just hangs there.

 

Great, thanks again. You designed the harness upgrade? Cool!

 

Great quality harness and close to double the light output. I haven't restored my foggy yellow lenses yet, but even so the improvement it noticeable!

My only suggestion would be include a few sheet metal screws for attaching the relay block, fuse holder and gold resistor to the truck. I had larger screws around the garage for mounting the relays and fuse, but had to scrounge around and ended up modifying a tiny #0 machine screw for mounting the gold resistor. Having a zip loc of hardware come with the harness would complete the harness kit!

Overall, its a great upgrade.

 

I did this upgrade a few months ago and have been extremely please, but last week I started having an issue with my DRL staying on when I turn the ignition off? The first time I was able to turn the headlights on then off to extinguish the DRLs. The second time, a few days later, I didn't notice them on and my battery ran down. The next time, my wife left them on and killed the battery. Right now I'm pulling an inline fuse to kill the lights when I park.

Where should I start my trouble shooting? The relays in the new harness?

 

Are you referring to DRL that utilize the headlights? (Vs amber indicators)

 

Yep, headlights

 

Update: I swapped the two relays on the upgrade harness and now the DRLs go out when the key is turned off, but with the headlights tuened on, they stay on with the key off. Previously, the headlights (as DRLs or as just headlights) would extinguish with the key off. Is one of these relays bad? Might head down to parts store and find out.

 

Update 2: now get no lights at all. Swapped the relays back and forth - no lights or DRLs. Reconnect the stock harness and now back to normal.

 

Update 3: checked the fuse, blown. Replaced it and reconnected the new harness and got the lights back, but weird stuff. When head lights are on as DRL, there is no increase in brightness when the headlights switch turned on. Also, if I click the brights, then click off, I lose normal headlights/DRLs and have only brights, if selected. Shut down, restart and get headlight/DRLs. Also, still have to shutoff headlights at shutdown vice going off automatically. Definitely in the harness. One or both relays? Local O'Reilly and Advance Auto were no help.

 

The harness operation is very simple. Low beam voltage detected, relay triggers low beams. High beam voltage detected relay triggers high beams.

The way the stock DRLs work is to run high beam at reduced wattage. Using the harness should disable the DRL function, as the relay is either on or off and is unable to run at partial wattage, the partial wattage provided at the OEM connector for DRL is not enough to throw the relay to cause the lights to turn on. At least on all other trucks. It is documented that this mod disables this function.

So in your last point, you mention your lights have no increase in brightness when operating as DRL vs on, this is because the relay is either on or off, so no increase in brightness would be expected. However, I wouldn't expect them to be on as DRL to begin with, so something doesn't sound right.

The lights continuing to stay on after the truck is off does sound like the relays are not behaving correctly, as they should release.

How do you have the harness grounded? Did you have your local autoparts store run an electrical systems check of the alternator/battery? Wondering if overcharging by a faulty alternator could cause this behavior.

 

The harness has been installed for about 3 1/2 months. Originally, I got the wrong harness and it didn't work at all. Called Ray and he sent me the correct harness. Once I installed it, grounded to a good ground, it all worked perfectly, including the headlights running as DRLs at a reduced brightness (apparently not disabled on mine), and the headlights cutting off with ignition off, regardless of whether used as DRLs or headlights, just as before the harness install. It's gotta be something in the relays, as I hooked up to the stock set up and all was back to normal. Didn't check the alt/batt, but will,check tomorrow. Gonna call Ray tomorrow as well.

 

Ok, just got off the phone with Ray. That guy is awesome. After much troubleshooting, guessing and voltmeter use, we determined that the relay on the low beam side (my DRLs use the low beam) was getting worked over and stuck closed. It uses a pulsed signal (buzzing like a swarm of bees) for the lower intensity low beams for DRLs. He's sending me a new relay and also is working up a go around to eliminate the pulsing and making the DRLs to be full low beam intensity - no constant cycling of the relay. For now, I put the good relay (from the high beam side) into the low beam slot, and left the high beam side empty - so, no high beams until I get the new relay - local auto shops don't normally carry this HELLA relay, according to Ray, and evidenced by checking the 4 shops here in town. Hope I don't burn this relay up too

 

Wow, both the original thread and this one are informative and I am going to order the harness and bulbs for an upcoming trip, after I check which type of switching I have. My question is for the the 12 volt gurus. I currently have a Blue Sea fuse block that I run my accessories from. Would hooking up to the blue sea fuse block instead of the battery diminish the output? For the record, I have had my truck since 03 and I have tried other bulbs through the years, but never had great results and/or the bulbs burnt out after a few months. Thanks for leading the way!

 

What is the gauge connecting the fuse block to the battery? Assuming it is large enough it would not diminish output.

Expect 6-12 months from the bulbs, they are rated at 200 hours, their life will be shorter than stock. I suggest ordering 2 pairs at a time. Practices like not starting your truck with headlights on will help prevent early burn out.

 

Cool. HIDs are overrated IMO. We're in the age of LEDs.
I got a pair of "8000 lumen", 5000Ks for around 60 bucks from aliexpress about a year ago, and I get people flashing me for brightness with only my low-beams on. I say 8000 in quotes, because with Chinesium products, they double the practical values for their ads.
I did my research heavily at the time, and the same ones I bought are repackaged and anodized in red on Amazon for a $40 markup - nonsense.
I literally don't think I'd even benefit from a light bar with these installed, and high-beams activated.
HIDs don't come close.