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89 quad headlights.. all on.. how to do?

camiswelding

camiswelding

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in my 89 I want all the hi and lo beams to come on with hi beam... whats the best way to do this.. I remember JC Whitney at one time selling a nice kit for this for our trucks... had the relay and all factory type plugs... havent seen it lately
who has done this ?
cam
 
Autozone now sells this kit, i bought mine through Jegs though.
Not so much factory plugs, but the kit comes with all the necessary hardware to do it correctly and clean.
 
I think painless & KC also make the kit. About 20 clams!
/forums/images/graemlins/waytogo.gif
 
Here's how I did mine. Using about $5-10 worth of relays from here. And here are the plugs.



885modifiedrelaycircuit.gif
 
thanks daniel DP 90k5... thats exactly what I wanted.... and I would rather do it your way than buy a kit with unecessary stuff at inflated pricing
cam
 
Thats too many relays, the kit i bought only uses one relay and a couple of connectors, and is also a very simply hook up, i had mine done within 20 minutes, all under the hood near the battery. all connections were made at the headlight wires themselves and of course a ground and the wire going to the battery. Trust me, buying the kit is a much more simple way, it not only gives you a diagram, but also written instructions as to which wire gets hooked to where. Very easy. /forums/images/graemlins/thumb.gif

also honestly i don't think thats an accurate drawing of the 89-91 electrical system to begin with, it doesn't use a standard ground setup like most vehicles. I only had to hook the wires up to one side (passenger) of the headlight system, and the reast were tied in automatically.
 
My setup not only turns all four lights on at once (only uses the lower relay for this) it also pulls direct power from the alternator or battery instead of going thru the headlight switch in the cab. I also used 10 and 12 guage wire instead of the wimpy, marginal 18 guage stuff from the factory.

Shorter and heavier direct power wires = BRIGHTER LIGHTS

Simple is not always the best. /forums/images/graemlins/peace.gif
 
I guess so, but they are not 500 watt lights running there, the wire that comes in the kit is more than adequate for the power rating of these lights.

And besides you aren't really adding more power to the lights, you are simply using the factory setup, but just adding the relay and wiring it up to "trigger" the low beam to stay on when the brights are on.
 
Actually, he is right. Power routed through yards of small wire and the main switch drops the voltage at the light. Sometimes as low at 10V or lower. Running shorter lengths of heavier wire directly from the nearby battery (or alternator) provides a full 12-13 volts to the lights. This is a common "better lights" modification.

The "all on" modification is a different mod that does just what it says. However, if you don't make the changes suggested by the more complex diagram, you may cause damage in some cases. The factory circuit (including the switch) is somewhat marginal in the factory configuration. It was not really designed to supply enough amperage to keep all 4 lights on at once. Using the cheaper kits turns them on anyway, and I've heard 2nd hand reports of damaged connectors and light switches due to the higher loads.

So, putting the relays out front gives you full voltage to the lights with wires that can easily handle "all on" voltages (or even upgraded light bulbs) and keeps the amperage off the factory circuit. Adding the jumper relay to trip the low beam relay when high beams are on gives you the "all on". Nice 1-2 punch that gives you a strong, reliable system (assuming good quality relays are used).
 
BTW, unless I'm missing something, you could simplify that diagram by triggering the low beam relay off the high beam relay output. That eliminates a relay which is a point of failure and extra work/expense. You also don't need high V/A at the all-on relay, so you could jump 86-87 and eliminate a fused link while keeping 3 relays if there is some reason to do so.
 
question,, i have a 89, with the four lights. can you use 4 hi-low lights instead of one low and one high. this way all lights are on at low beam as well as high..
 
Sorry, not to be an ass, but it's not an opinion, it's physics. Voltage does drop along a length of wire, it's a resistor that varies based on cross section area and length. The smaller the wire, or longer the run, the more the drop. This drop results in loss through heat (which is why small wires burn up easier). It's a simple fact that the lights *can not* see full voltage after routing from source, to the dash, through the switch, and back to the lights. That voltage drop means the lights can not produce their rated wattage due to W = VA. Lower V than rated means lower W, which is lower light output. Shorter runs of heavier wire result in less drop so you can at least approach the rated (legal limit) output of the lights.

As for the “all on” mod; try to push too many amps across the wire (particularly in a bundle) and you melt the insulation. Likewise, the switch can only handle so much amperage before doing a melt down. In the normal case you have roughly 4.5 amps per bulb on low beam, and 5.4 amps per bulb on high. That comes to 9.16 amps total for low beam circuit and 10.83 amps for the high. So the "all on" mod pulls 20A across the power wire to the switch and through the switch, basically doubling the factory load. It also pulls 20A through the high beam wire alone on it's way to the relay. Check the wire gauge load limits and you'll see that the factory harness is right on it's limit there, and that limit is based on open air runs, not "in a bundle" and wrapped in a harness loom/tape.

[Note: For the engineers out there I am actively ignoring cumulative and parasitic effects for simplicity.]

Check out this page for a handy calculator and table that indicates amperage ratings for wire size and voltage drops based on wire size, run length, etc. I found this on Google, but there are others.
 
With the voltage improvement mod you technically could (assuming suitable materials to handle the load), but you'll have non-technical problems with that configuration. People will assume that 4 lights equals "high beams" and you'll get flashed allot. You also may be stopped by a cop who makes the same assumption. And, I'm not sure, but it may be illegal. I'm not sure if the legal low beam limit is 55W *per light*, of if it's a cumulative total wattage maximum (i.e. 110W) for low beams.
 
thanks for the info. for the law part, in iowa you can have a total of 4 lights on high or low or driving lights.
 
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