Since then, I have came upon a much simpler relay-less method of providing switchable "on demand" brights/dims being both ON at the same time and still controlled by the dimmer-switch.

It is really very simple.

The dimmer-switch has ONE in-coming wire that is HOT from the head-light switch.

Then, the dimmer switches this current to either BRIGHT or DIM wires to the head-lights.

Splice a wire into the in-coming wire of the dimmer and route it to a dash-mounted SPST switch.

Splice another wire into the DIM wire on the out-put side of the dimmer and route it to the remaining terminal of the SPST switch.


When this SPST switch is OFF, the headlights will function as normal.

When the SPST switch is ON, the DIM relay will remain ON at all times that the head-light switch is ON, with the dimmer simply switching the BRIGHT lights ON and OFF.:cool:

On my Fords, I have always just bypassed the dimmer switch all together for the low beam circuit. What I have always done is cut off the feed to the low beam circuit and hook it to the power supply for the dimmer switch. This way the low beam circuit is engaged so long as the headlight switch is on. I don't really see a need for it to be switched or relayed, no need to complicate the circuit. I've never been in a position that I wanted just the high beams on and not both.

I have been debating how to wire up relays on my 92 and keep the DRL's working. I'm thinking that the power feed for them needs to get hooked to the headlight side of the high beam wiring, bypassing the relay altogether. But, at the same time, I am going to be swapping my truck over to H4's and 100/50W bulbs like I've run in my Fords for years, so, I don't know how that power supply is going to like the extra draw. With said bulbs, I have also found it necessary to run a separate breaker for high and low beams, I just didn't feel comfortable running a single 40A(may even have needed more, 30 wasn't enough) to handle both circuits.

Thanks for the excellent write up Jim! I have been contemplating tackling this project in both of our trucks for a while (especially after replacing three melted headlight switches and driving home the last time holding the bright light switch back) but I was a little hesitant. I am no electrician, but I manage most mechanical projects pretty well. I think I can do this now!

an inexpensive heat gun is sold at most hardware stores in the paint section under the guise of a paint stripper.

Jim,

If you built these harnesses and sold them I would buy one without a doubt.

I just don't have the time to do useful mods like this on my truck. I have to take it to a shop.

I just used a Diode between signal wires for low beam & high beam to keep my dims on with my brights.

Just did this to my truck, upgraded from stock headlights to Bosch H4's with 80/100w's and it was a little bit better.

Did the rewire with the 2 relays and wow, way way way better. Thanks for the idea.

Sticky vote
 

Well, if this isn't in the Sticky already, it should be! Outstanding!

Does anyone have a part number for the relays that I need for this? I've dont jim's A/c compressor switch relay and it worked great. For that i used a BorgWarner p/n: R3011. Do I need to use a relay with a diode for this one as well? Any help would be appreciated.

Use a genuine Bosch ISO Relay 5 terminal; can be picked up at most auto stores; Napa carries them for sure.

thanks for the reply i know that much but whats the part number. theres a few options and i want to make sure the circutry routing etc is correct.

If someone knows the original Bosch number then atleast i can look and see if its a diode protected relay or not. Thanks for any help guys

If anyone could answer that would be great, i think i've found some relays to work. What I need is a 30a Single Pole double Throw relay correct? thanks for the help guys

Here are some numbers:

Bosch 0 322 209 150
(This is the most commonly used relay)

Tyco V23134-A1052-C643

If you do decide to use the relay with the internal diode just make sure that

Term. #85 = Ground
Term. #86 = (+) 12 Volts

When installing relays on any critical circuit I would urge you to use a good quality ISO relay because they ARE NOT all created equally and an inferior part could fail leaving you without headlights on a dark mountain road and could have disastrous or even fatal consequences.

A quality relay to me would be Bosch, Tyco, Potter Brumfield, BWD.

Also rebadged for Napa/ Echlin are fine.

If you can get it for $1.00 don't trust your life on it.

Jim

Thanks mr lane cant wait to see my lights after the upgrade. I plugged one of the new lights in w/ just the factory harness and tried it out just to see comparison before the upgrade and mannnnn its a huge difference already. The silverstars are a "Whiter Brighter" light almost a total white, Where as the old sylvania stockers are just a dull boring old worn out yellowish look. Ya'll gotta do this upgrade[director][director][director]