First, Did it make the improvement you expected?

Where did you physically mount the relay, in front of the Rad support or behind (this is my main question) and why?

What size wire did you run to power the relay and where did you run it from? ( I have a trunk mounted battery)

My application is a daily driver driven in tropical south Fla near the coast and I am wondering if I am asking for future connection problems, etc putting a relay in the very front exposed to highway driven rain, dirt, etc

Best thing ever. Lights don't dim at idle. This along with the ammeter bypass is the way to go. I mounted mine under the battery tray. I used the same wire as the factory, I believe it was 18g.

y 3 relays?

High & low beams, I also did the running lights.

I'm going to do the rears & brakes next.

I fit ALL THE RELAYS under the dash ( hidden by kick panel ), and took the power from ammeter stud, alt side.

didn't cut a wire, simply removed the terminal from original foot switch plug, instaled on relay plug, and run back the other wire ( signal ) on same color between foot switch plug and relay plug with new terminals, so you'll never see a relay anywhere or diff color wires, or splice anywhere.

made teh same on each speed of A/C-Heater.

relays are away from engine bay heat, dust, grease, water and rust caused by elements. and won't tell any splice or added device on engine bay

That sounds tidy and clean, but doesn't that kinda negate the one of the main reasons for using relays in the first place?

12 gauge wires, relay secondary power feed from starter relay. Don't forget to isolate the gound circuit from the factory harness too.

Very Nice

Are the extra 15A fuses part of the the headlight relay circuit?

The fuses protect the secondary power feed to the headlamps and relays, ended up having to bump up the high beam fuse to 20amps. I’m running 2 H1s and 2 H4s.

I used the relay box out of an intrepid and wired relays for the horn, high and low beams. There are extra slots should I ever decide to run an electric fuel pump or cooling fans. The box is powered right off the alternator and is fused and has a fusable link protecting it. Headlights never dim any more. The box is mounted on using a piece if stainless that I bent and polished.

Mine are in front of the radiator support, its just easier to do this on an A-body for packaging reasons. I took power from the starter relay (I also have the ammmemeter bypass, etc done to my car), have a 20amp fuse (just one, shouldn't need 2), connected to a 12 ga wire that branches off to the two relays. From there I just interrupted the stock wiring harness and connected the original feed to control the relays and the output to the output of the relays. I made a ground strap that goes to the same post as the parking lights are grounded to. The headlights are now over twice as bright.

With relays though, the idea is to keep the relay as close to the headlight as possible as to minimize the voltage drop (especially if using any factory wiring). I would also make it a point to crimp AND solder the connectors that you use as well.

The more load you get off the factory dash harness, the better!

My '67 Fury convertible headlights used to go on and off momentarily at times before I installed the relays. They no longer do that and are noticibly brighter now. By installing the relays you are taking a large load off of the headlight and dimmer switches. It is really worth doing.
John

“Shouldn’t need 2 fuses” with stock sealed beams, or even sealed beam Halogens maybe not. Two reasons I have, first redundancy, should a fault develop in either the high or low beam circuits while I’m blasting down some dark country road some night I can flip over the other functioning headlamps. One fuse, I’m screwed. Secondly, as mentioned I’m running higher wattage bulbs, both low beams =110 watts or about 8.2amps @ 13.5volts. All four high beams=230 watts or 17amps @ 13.5volts. A lot contemporary cars today will fuse protect each side as well as each circuit, again redundancy.

Is there a basic schematic that you guys go by? How does it all tie in to your electrical? I'm interested in finding out

Nice drawing 1Wildrt. 71rm23 I believe your color codes in the forward harness will likely be the same as my “72rm23”, low beam-violet/white and high beam-red. You will need to parallel the additional 5” inboard high beams off the high beam circuit on the 1wildrt’s diagram.

I did the headlight relays and the amp guage by-pass. After doing this I highly recommend both procedures (amp guage bypass first, then relays).

FWIW...

Did I get the expected results?
Yes and no..

Yes, when running down the road the headlights
are very bright and the interior dash lights and everything runs much better... The car even
starts and idles better...

However, when sitting at a stop light,
at idle, in the rain,
defroster on, wipers on, headlights on..
you still have a fundemental problem

At idle, the mopar alternator does not put out
enough amperage AT IDLE to feed all of this stuff if it is all turned on... for very long
it starts to draw (and draw quickly from the battery) which means the voltage starts to drop
meaning the lights will start to dim...


So, if you sit in your driveway with the car at idle, and turn on the headlights (and brights)
you'll notice over time ( a few minutes) that the voltage will start to drop....and drop ....and drop...

The problem is immediately alleviated if you crank up the idle (rev the engine) or put it in gear and go... The idea being, chrysler never intended on you sitting in your driveway doing this. only pulling up to a stop light for a minute or two..

ANYWAY..if your driving your car with lights on,
radio on, defroster on (or AC on) etc.. at night
and you pull up to a stop light and wait your going to notice a slight dimming of the lights

So it's not a flawless fix... but it is a substantial improvement... especially while going down the road.

I am planning on adding a relay for the AC.
I spoke to Mark at MAD Electrical and he said the
only way to alleviate this is to go with a high
amp alternator which puts out more juice at idle..

The big question is: exactly what is the idle output for a stock 50 amp / 60 amp/ 78 amp
alternator and what is the idle amp output
for the upgraded powermaster alternator or
FBO alternator...

Is it really worth it to upgrade the alternator.
FWIW, my 2002 truck NEVER has this issue...

Oh well,, it was a lot of fun to do this

I put my headlight relays on the radiator core support on the inside by the battery...
right next to the forward light harness.
I routed the power wires directly from the alternator BAT terminal across the radiator core support (its hidden with the forward light harness which routes the same way) ...

I guess I should say I didn't think I needed two fuses because I only have a single headlight on each side. only one filament on at a time! might be different for you four headlight guys.