Proper headlight upgrade

Thanks. So I guess the answer is "ground switched "

 

Hey guys, I have read up on doing this to my '01 DC w/o DRL....I just cleaned up my headlight lenses so now I am on the market for a different light set up. So this is entirely plug & play, also will reduce bulb life (not a big deal) but I can use any h3 bulb, right? I'd like to get it done, asap

 

Don't you have H4?

 

If by H3 you meant H4, yes. The standalone harness reduces voltage drop causing the lights to burn brighter. To get the full benefit of this upgrade you'd want to run high wattage bulbs, non-coated for maximum performance.

You can see additional bulb recommendations at the beginning and end of the ultimate headlight upgrade thread:
https://www.tacomaworld.com/threads/the-ultimate-headlight-upgrade-not-led-or-hid.398066/

 

One more benefit is that high current does not run though light switch. Light switch handles relay control current like in modern cars.

The stock design of 1st gen headlights is very promitive an very outdated even by 1995 standards.

 

yup i have it hooked up exactly like the picture.

nothing over 1 Volt when the headlights are on and 14 Volts when the headlights are off (thats with the truck running).

if the truck is off I get under 1 volt weather the headlight switch is on or off.

but definitly nothing near or close to 12 volts when the lights are on (with the truck running or not).

 

You mention "on" in both scenarios but I think you were a victim of auto correct. I just went and rechecked my truck. Never any voltage in the left plug, regardless of on/off. Do you have daytime running lights? When getting readings on <1v you can assume it is noise for this exercise.

 

I have both harnesses at the house now. I ordered the first one before testing and and after testing, I thought I had ground switched so I ordered the other one. Well, I just did another test with the multimeter, and here are the results. With truck running, headlights off, DRL on, I get 3 volts on the common. When I switch the headlights on, the volts drop to .2? Does this indicate conventional switching? Based on what I am reading, I can treat the .2 as none, and the 3 volts in the off position is related to the DRL? I have both harnesses here, so I just need to pick the right one.
Oh, and I have 6 gauge wire going to a blue sea auxiliary fuse box. Should I hook up to the fuse box or the battery? Thanks again. Looking forward to night vision!

 

Do I read correctly, you have factory DRL? Like Canadian version? I wish I noticed it before. If so, the circuit is much more complicated. It is hard to classify "switching" method. There is a light selection (Hi/Lo) relay on the +12V side but also DRL Relay on the "ground" side. The "ground" side (the common for both filaments) is switched either to the ground by DRL relay (stupid name it is, as this relay closes the circuit when DRL are off and lights are on) or to DRL Relay Control Box (equivalent of DRL resistor).

So if you have DRL turned on (all the logic requirements are met like releasing hand brake, getting out of park, engine running, light are off etc) the bulb common is grounded via DRL Realey Control Box and that would limit the current (hence reading 3 volts on it).

So simply saying you are screwed . I think new harness will not work with DRL version of headlights (at the best you will lose DRL functionality). I am not familiar if such harness even exists.

 

yes, it is factory DRL, but they come on whether the parking brake is engaged or not. When I start my truck, DRL come on automatically. If I turn on the headlights, the brightness increases, but it's the same bulb. I pick up 3 volts on the common when just the DRL are on. When I turn on the headlights, it drops to .2 volts. It's a Texas Truck and I have owned it since new, so nothing has been added.

 

Whoops! I was wrong. If I start the truck with the parking brake on, no DRL. I never knew that. When I release the brake, they come on. Checking voltage, without DRL on, the common showed .1, with DRL on its 3 volts, and with headlights on its .2 volts. I'm thinking it's conventional now. Help?!

 

Here is from Electrical diagram:

1. DAYTIME RUNNING LIGHT OPERATION
When the engine is started, voltage generated at TERMINAL L of the generator is applied to TERMINAL 9 of the daytime
running light relay (Main).
If the parking brake lever is pulled up (The parking brake SW on) at this time, the relay is not activated, so the daytime
running light system does not operate. If the parking brake lever is then released (The parking brake SW off), a signal is
input to TERMINAL 11 of the relay. This activates the relay, so current flows from battery to the HEAD relay (Point side) to
TERMINAL 4 of the DIMMER relay to TERMINAL 1 to HEAD (LO LH), (LO RH) fuse to TERMINAL 1 of the headlights to
TERMINAL 3 to TERMINAL 1 of the daytime running light relay (Main) to TERMINAL 2 to GROUND. This causes headlights
to light up (Headlights light up dimmer than full brightness.).
Once the daytime running light system operates and headlights light up, headlights remain on even if the parking brake lever
is pulled up (The parking brake SW on).
If the engine stalls and the ignition SW remains on, headlights remain lighted up even through current is no longer output
from TERMINAL L of the generator. If the ignition SW is then turned off, the headlights go off. If the engine is started with the
parking brake lever released (The parking brake SW off), the daytime running light system operates and headlights light up
when the engine starts.

All what you described agrees with diagram for your truck.

 

Now there is a good thing for trucks with DRL. When headlights are active the current runs quite short distance, just three relays. The high current does not run through the headlight switch (which I think is the weakest point in Tacoma circuit without DRL). And each filament is protected by its own 10A fuse. Just the bad think is you can't use external common harness and preserve DRL functionality, but would you really need external harness in your case. All high current elements are under the hood in main Fuse box, and they are as close to the battery as possible. Also 10A fuse on each filament should survive 85W bulbs. It is hard to tell about DRL Main relay (DRL resistor thing) if it agrees with 85W bulbs instead stock 65W but I suspect it shouldn't mind. So external harness might be unnecessary improvement.

 

The plot thickens. LOL. I just got off the phone with Tom at Susquehanna and he's doing some digging.it looks like MD11fr8dog may have come across this issue and they built a workaround for it. I might be sending the harnesses back.

 

Also, Norton, with an 04 with DRL, used the conventional harness, BUT he had previously disabled the DRL. Maybe that the trick?

 

Dig a little, get a lot. Talking with Tom from Susquehanna, we decided to try the conventionally switched harness. As soon as I released my parking break, the relay started buzzing and my head lights came on, but my headlight switch was off. It was trying to run my DRL, but at a higher intensity. I turned off the truck immediately. I read up an disabling the DRL and found this : http://www.customtacos.com/forum/1701245-post43.html It appears that DRL have been wired differently depending on which generation of first gen you have. I suspect that the later model of first gens (2001-2004) are the ones with issues with the harnesses. Norton, if you are reading this, how did you disable your DRLs? I think the harness will work if the DRL are already turned off.

 

to tag someone, type this @ symbol in front of their tw username.

Like this @Norton

 

Thanks, @Digiratus ! Learned a few new tricks today!

 

I'm reading but that was a LONG time ago in a forum far, far away. IIRC, this is how I did it...

 

Just did this on my 97 with the Hella H4 conversion ballasts to replace the crappy sealed beams. Went with the 100w harness and Hella 100/80w bulbs.The kit came with 60/55's but I didn't think the 100/80's looked so bright they would blind anyone. By far the best lights I've ever had. You get the brightness of HID's but they project so much further, definitely recommended to any first gen owners.