Headlight Relay Yes No

-
Y

yellow1

Active Member
Joined
Feb 9, 2011
Messages
27
Reaction score
0
Location
Brandon,Ms
Putting in a painless style wiring harness in my 71 Demon. New stuff says nothing about putting a delay switch in the line before the Hi Low switch like the Factory Diagram shows. So the question is, do I need it and what exactly does it do anyway? Thanks for any help!
 
So the question is, do I need it and what exactly does it do anyway? Thanks for any help!
Click to expand...


yes you should use one. it takes the load off your switch and also puts a full 12 volts to your lights.
 
Relays are good.....power robbers are bad.

Load on ammeters is bad....load on battery without going through ammeter is good.
 
Thanks for the input. I am not sure what the old one looked like. I think it might of been on drivers side above kick panel maybe. I will check with summit and see if they have one, if I cant find one elsewhere. Thanks
 
Absolutely, and you might consider a relay panel under the hood, especially if you have other added loads. I use a junker Voyager box like this:

image.php


which has lots of relays, headlights, ignition / charging, fuel pump, injection, and a couple left over, security, whatever
 
relays will help with load, as stated, and also provide much brighter headlights... a must for a driver or cruiser in my opinion. I installed 2, (because I did it after the bright switch), one for low/high beams. Its a simple mod if you're doing the whole car, and well worth it...

JOE
 
Using relays to carry the headlight power is a great solution. Takes load off the switch.

Not sure of wire size in a painless kit, but, that's where they sometimes fall short. Undersized wire. IMHO, you want as much voltage at the bulb, that requires the biggest wire gauge that can be run and ideally the shortest run possible from the power source.
 
This is a confusing question. The title asks about relays, but the question asks about a delay switch. Yes relays are a big help and no you don't need a delay switch.
 
Yeah I'm confused also. Factory diagrams shows a delay ?
Newer cars use relays for a few advantages. 1st and most important they take the circuit load off of the manually operated switches. 2nd, Less amperage equals less switch and lesser gauge wire inside the cabin.
3rd. The relay and those greater components can be placed near the need further reducing materials required.
Placing a single headlight relay before the dimmer switch doesn't do any of those things. Dimmer switch is manually operated switch ( with foot rather than hand operated ), and vulnerable to environmental elements too.
Aren't yall glad I have spell check LOL
 
Yes, my bad on the relay- delay stuff. The factory diagram actually says both. I am in a learning curve here. Anyone have a simple looking diagram for putting a relay in after the dimmer switch?
 
[ame="http://www.ebay.com/itm/H4-Headlight-Relay-Wiring-Harness-2-Head-Lamp-Systems-Fix-Dim-Lights-7-Round-5-/281146739569?pt=Vintage_Car_Truck_Parts_Accessories&hash=item4175a6cb71"]H4 Headlight Relay Wiring Harness 2 Head Lamp Systems Fix Dim Lights 7" Round 5 | eBay[/ame]

Here you go....not the exact part number but this guy has the right ones and they work. I have done 3 conversions.

Red wire to battery, black to grounds, plug the male connectors into the old headlight sockets then plug the headlights into the new ceramic sockets. Everything else remains the same.

Done in 20 minutes.
 
I would think a direct connection to the battery to feed the relay should include an auto reset breaker. Safety first.
 
The kits I build, parts alone, cost more than the complete kit from e-bay. I've taken one of those kits apart and seen enough of the chinese assembly quality to know that it's not the best in lots of cases. Unfortunately now, almost every headlight ceramic connector comes from China.

Pulling headlight power at the battery on older mopars is not the best approach with the bulkhead/ammeter.

There are a lot of unseen issues that get missed in these kits. If people are cool with the wire covering installed, parts used and build quality, go for it.
 
You don't need headlight relays if your headlamp switch is good (new ones are cheap), all connections (like in the bulkhead) are pristine, and using factory rated bulbs. A relay can be a kludge to get around those problems, but perhaps fixing the true problems is easier.

A relay may be necessary if high-load after-market HID lamps. If totally rewiring the under-hood, relays are certainly smart. As 67Dart273, I did that, installing a newish (95-99) underhood relay/fuse box in 2 of my old Mopars (black box in my avatar). In that case, I had plenty of relays so used one for low-beam and one for high-beam, plus replaced my factory starter and horn relays. I wouldn't kludge-on individual headlamp relays like the Frankenstein jobs some people show.
 
KitCarlson said:
I would think a direct connection to the battery to feed the relay should include an auto reset breaker. Safety first.
Click to expand...

It does have an inline fuse for that purpose...you could easily modify it to a circuit breaker if desired.
 
crackedback said:
The kits I build, parts alone, cost more than the complete kit from e-bay. I've taken one of those kits apart and seen enough of the chinese assembly quality to know that it's not the best in lots of cases. Unfortunately now, almost every headlight ceramic connector comes from China.

Pulling headlight power at the battery on older mopars is not the best approach with the bulkhead/ammeter.

There are a lot of unseen issues that get missed in these kits. If people are cool with the wire covering installed, parts used and build quality, go for it.
Click to expand...

I have installed three and I will vouch for them. Quality is as good as anything I have gotten from anywhere else. Parts work fine. Wire is correct gauge and the relays are the same ones you get an any auto parts store. Look at the feedback comments and see for yourself.


The deal on the bulkhead connector is back assward. By running straight to the battery your eliminating load that would normally pass through the bulkhead connector thus eliminating heat and stress on the old crappy set up. I don't care how new it is there is a reason all newer cars use relays. Hell if you have an old ammeter set up you should eliminate it anyway. The voltmeter conversion is so simple there is no reason other than 100% correct resto to have it ammeter style.

I'm not knocking the kits a member sells on here. Matter of fact had I known that they existed elsewhere I would have bought them here. Just saying it is a great idea to do the conversion. NO DRAWBACKS!
 
momoparman said:
The deal on the bulkhead connector is back assward. By running straight to the battery your eliminating load that would normally pass through the bulkhead connector thus eliminating heat and stress on the old crappy set up.
Click to expand...

Do not kid yourself. Relays ALONE does not cure this. Whether you rob power from the alternator stud or from the starter relay, "at some point," high current is still going through the bulkhead, UNLESS it has been upgraded / modified, or at the very least brought back up to "as new" standards.

Even Ma knew these were inadequate-----look up what is know as "fleet wiring" sometime. Essentially, this is very similar to an ammeter bypass, except that it runs new / larger wires through separate grommets, to relieve the bulkhead connector

These type connectors are the same essential type that are commonly used in household electric furnaces--at a nominal 20A of current. They fail "all the time." One of the checks you do when servicing a heat pump / electric furnace is to inspect the electrical connections. I've replaced dozens in the years I did this service work.
 
?


How do you load it up if your dropping 10 amps? That load runs from a to b that means from ground through the headlights through the relay contacts and to the positive side of the battery. The load never goes inside through the bulkhead connector.

If you do this modification the lighting load will not pass through the bulkead or the ammeter period.
Thats what this thread was about.

Take the advise or not.

Good luck.
 
momoparman said:
? The load never goes inside through the bulkhead connector.
Click to expand...

Of course it does. It depends on which is "more positive," the alternator or the battery.

If you are stopped, let's say for an extended period, the load comes from the battery to the starter relay and to the headlights

But if you are RUNNING down the road, with an otherwise factory bulkhead connector and ammeter, the power path is ground.......headlights........battery stud.........fuse link........bulkhead.....ammeter.........BACK OUT the bulkhead.........to the ammeter output stud.

The battery is NOT the power source when the alternator "has the load."
 
Not seeing it. Not saying it isn't there, just not seeing it.

I tap into 12VDC power at the battery stud on the alt or starter, doesn't matter in my case (& maybe that's why I'm not seeing it), for the high current side of the relays. I control the relays with the original light switch and Hi-Lo switch by plugging into one of the headlight sockets.

Other than control power, which I just replaced the headlight loads with relay coil loads, nothing passes thru the firewall.

If the ammeter is between the alt and the battery (been too long since I changed all of that to recall how it was), then it matters where you tap in for the current power. Needs to be on the Alt side. That assumes that the alt can keep up at idle. If not, you're screwed until you upgrade it so that it can.
 
My opinion... Issues with bulkhead connectors and ALT' gauges are blown waaaay out of proportion by the internet. I suspect for every 1 failure reported there are dozens more out there with no fault. Some will link bulkhead connector and those Madelectrical webpages to every electrical fault. Truth is the actual fault probably is/was somewhere else. Only the evidence or results appear at that connector. Bypass the connector equals moving the future fault evidence somewhere else, and likely to a place where it isn't so easily found. So... Headlight circuit changes or no, If/when there is a fault and or overload occurs at wiper motor, blower motor, whatever, where will you find the melting/burning ? Outside the firewall or all about under/behind the dash ?
I stated before. Headlight relays or any relays are used to lessen the loads on manually operated switches. In our cars, increased load could only come from different that OEM type bulbs. If OEM type bulbs are used the headlight switch will only be replaced due to the historically typical failure of the included dimmer rheostat.
Again just my opinion.. Those who suggest "bypass this and that" should first take long look at how and why it was built a certain way in the first place. They just might find there was a 'method to the madness' and they aren't really smarter than those OEM engineers after all.
 
You must log in or register to reply here.
-

Back
Top