jmkord8703

So i just fried my light switch wiring harness. I have been putting off adding these relays for my headlights... apparently too long. I have added extra running lights over the years and the other night all my lights went out except my head lights. After some searching i found one of the marker lights where the 2 wires had touched and fried. I repaired it, preplaced the fuse and still no lights. Figured out it was in the switch, bought a new one, took it all apart and realized the switch is fine. The wiring harness is melted. So here is my question. Will running these relays for my headlights help prevent it from frying again because of my extra running lights? Or is it completely unrelated?

ofcmarc

You would have to run a relay for the running light circuit as well. The write-up in the sticky by Jim Lane does the HEADLIGHTS only.

IIRC There was a relay install write-up for the running light circuit by Member chrisreyn a year or so ago. Try the search engine......

Rampage1967

Here's another suggestion for the biggest improvement from headlamp relays. Connect your power for your headlamps directly to the BATT terminal on the alternator. Run a heavy gauge ground from the engine block to the radiator bulkhead & the headlamp grounds. You will be amazed how much brighter all of your lights will be.

ofcmarc

Found it.
https://www.dieseltruckresource.com/...ighlight=relay

chromehound

I don't know if this will help

http://www.humanspeakers.com/audi/headlight-simple.htm

Richie O

I went crazy on my 92. I have relays for high beam, low beam, trailer and rear tailights, rear blinkers and stop, and backup lights.

BearKiller

I have High-Beams, Low-Beams, REVERSE-lights --- many reverse-lights, and the multi-tude of flashers, all on relays.

The flashers I have on tandem relays, in order to halve the arc, and thus extend contact life.

The brain-box for the flashers is in a plastic tool-box that resides underneath the goose-neck trap-door; you can hear it CLICK---CLICK---CLICK from a hundred feet away with the engine running.


I don't trust the bejillion trailer-markers, nor the many truck-markers, to any relays; I have these hard-wired through BIG toggle-switches, big truck style.

Jim Lane

Connecting your headlamps this way while using Silver Stars could cause then to burn out considerably faster.

Here is why on a truck with factory stock wiring the alternator is connected to the battery through 6-gauge wire and a connector, if you were to connect a voltmeter at the alternator you could see voltages as high as 15 volts while the battery was only 13.8 because of all of the resistance in the connecting wiring, the voltage at the battery is more stable because the battery acts as a buffer to smoothen out the alternator.

With the factory wiring when the battery is trying to recover like when after the grid heaters have cycled or your plow pump was cycled you are producing a voltage drop and heat in the wiring.

Because of this I would recommend is to connect your headlamp relays directly to the battery.

Here is what to do if you want to drastically improve your charging system.

Install a new alternator charging wire to the battery, when I still had my 120-amp Nippon Denso I used a length of 4-gauge welding cable from the Bat terminal on the alternator to the battery (+) terminal through a 160-amp fuse, AND a 4-gauge ground wire from the alternator case bolt to the front of the block.

Here is the cable I have on my alternator, it replaces a 6-gauge wire.

Also see the 2 small 10 gauge wires connected to the battery post? these supply the high current to your grid heaters, about 100-amps each.



Here is how I terminate my cables.



Here is how I connected my ground cables.



Now the battery will receive full output from the alternator, all of your lights will be brighter and your blower motor motor will run faster.


My headlamp system consist of 4 Bosch relays, one relay for each filament, Low's High"s Left and Right with the low beams have their own 20-amp self resetting thermal breaker while the High beams are fed from a single 30-amp self resetting thermal breaker.

Current from the relays to the headlamps is carried on a 12-gauge wire with a 12-gauge ground carried all the way back to the battery with a ground tap at each headlamp.


Now I have my 160-amp 110-555JHO Leece Neville alternator and my charge wire is made of 2-gauge welding cable to my main battery through a 200-amp "T" fuse.



To make it efficient there is also a 2-gauge ground wire from the alternator the the block, block to the frame and block to the battery.

This is taken at the battery idling.



After building a voltage regulator I have reduced my voltage to 13.1 volts at each headlamp with the truck idling, at 13.8 volts and gobs of amps the lights are insanely bright but they do not last too long.

I did this in an attempt to get a longer life out of my Silver Stars but still get superior lighting from them.

Just a few thoughts.

Jim

QIK2D

hey jim, i was under the understanding that 2 ga wire was rated to carry 180 amps. if you're fused at 200 won't the wire burn before the fuse pops? what is a good way to determine the fuse rating when wiring stuff?

daryl

NJTman

Hey Jim

What's wrong with under your hood?

Not one drop of oil, smudge of grease, lick of rust ? That's not your truck, it's a picture of a Dodge in a museum.




Showoff !

Jim Lane

Oh hey there is a bit of oil on my truck, there is a small leak in the side cover again and I have a leak from my rear main seal. I have all of the parts but I just cant get myself to pull the transmission to do a 20 minuet job.

I like to keep my engine clean, the engine compartment gets washed every time the truck gets washed, I use Simple Green in either a spray bottle of from my air powered sprayer, it gets hosed down, dried with compressed air and then wiped down with a towel.

All of the wire looms are blown out, connections checked and linkages oiled using turbine oil.

Then the engine is then run to allow any of the remaining water to evaporate

I hate leaning into the engine to check the oil or to show it off and get my clothes dirty.

Jim

Jim Lane

2-gauge welding cable is good for 200-amps @ 100 feet.

The total length of my alternator feed is less than 6 feet and unless I am running my inverter my alternator shouldn't be at maximum output for more than a few minuets.

I have several pairs of jumper cables I have made that are 35 feet long of #2 welding cable I have used for starting 330 Cat engines in Class-A motor homes with dead batteries off my truck, after connecting to their dead batteries I would parallel my batteries and then bring up the idle to about 1200 RPM and then start the Cat engines, the cables would get warm but never hot to the touch, the engines would start with no problems.

Welding Cable Amperage Chart.
http://islandsupplywelding.com/weldi...le-chart-3.htm

The fuse is there to protect my batteries and the cable in the event of a catastrophic short should the alternator diodes short out the alternator should limit itself.

I have had starters and parallel switches short out on transit coaches and the 8-D batteries would explode or the terminals melt off the battery before the cables melted.

I will watch it and if it ever does look like it is at its limits or if I install a larger alternator I will install a larger cable.

I always have access to my Klein cutters to sever a cable if need be.

http://www.service.kleintools.com/To...20CUT-HLCABCUT

Jim

jmkord8703

Thanks for all the info guys. I got my headlights done. Now I'm gonna do my running lights. What size fuse should i put in on this one? the same 30 amp circuit breaker? or a smaller one? thanks

NJTman

I'll say...

More than just being clean, I was blown away at the condition of the engine bay itself. I guess it's all where you live, or where the truck has resided for the last 18 years, that makes the difference.

Amazing piece you have there.


T.