79 cj7 headlight upgrade ??? - JeepForum.com

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post #1 of 12 Old 10-16-2011, 09:18 PM Thread Starter
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1979 CJ7 
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79 cj7 headlight upgrade ???

looking for INEXPENSIVE and SIMPLE upgrade for my original 79 cj7 headlights...
Are there better OEM replacements... or will it involve re-wiring and relays???
Not really wanting to put a lot of money and time into it, because it is not my DD... but would like more light if it is worthwhile.

'79 CJ7, stock 304v8, T150 3spd, Dana 30, AMC 20, Dana 20 T/C, Flowmaster 40 dual exhaust, 4"spring lift, 1-3/8"shackles, 35x12.50 Toyo A/T, 15x10 M/T Sidebitters, rear 1pc axles, Warn front bumper w/VR8000, custom 5" tube rear bumper, nerf bars, Tuffy (console, glove box, side rear speaker/storage boxes), new dash panel and Autometer gauges
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post #2 of 12 Old 10-16-2011, 09:30 PM
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Rewire with relays is the best, least expensive way of getting more light out of your headlights. It won't matter what bulbs you put in them, if the original wiring is still there, you are not going to get 100% out of any bulb you put in there!!

The reason is they can't get enough amps to the lights. The voltage has to come from the battery, through the wiring to the switch, and through back to the lights. All of that original wire isn't big enough gauge to start with, as well as the amps going through the switch. This is why the headlight switch fails most of the time. With a relay setup, you are only having the relay coil amps going through that small gauge original wire, which isn't much at all. When the relay is switched on, all of the power from the battery is available for the lights, as, now, there is a direct connection from the battery to the lights.

I hope this makes sense, as I'm typing this way past my bed time, LOL!!


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post #3 of 12 Old 10-16-2011, 09:38 PM
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Agreed... But I'll add one more comment to the above. Make sure everything is well grounded too. Correct wiring sizes, relays, and good grounds will equal a whole lot more usable light from your headlights.

1985 CJ7 Project
Phase One : 5.3L Vortec/4L60E, Moser axles for AMC20, Twin Stick'd Dana300 - Completed
Phase Two: Bedliner, Rollcage, Seats, BESRK Rear Bumper w/ tire swing, Soft Top, and a few other goodies - Mostly Complete
Phase Three: Waggy 44 front, Scout D44 Rear, 4.56's, ARB's (F/R) SOA with YJ Springs, 35x12.50x15 BFG MT - Not Even Close to beginning

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post #4 of 12 Old 10-16-2011, 10:05 PM
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Ignorant question here... can't you just plug in some stock replacement halogen bulbs and go? May not be as bright as the great stuff on the market, but a lot brighter than factory. It has been many years since I have done this, but I thought it was still an option??

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post #5 of 12 Old 10-16-2011, 10:45 PM
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If you have stock headlights you have probably got sealed beam units. Very cheap, don't tend to rust but give poor light.

If you want to upgrade any 7" round light with an H4 bulb is a massive upgrade. The H4 bulb can be upgraded but as mentioned above if you want that benefit you are better running some larger cable and fitting a couple of relays at the headlights.

BagusJeep lives in Bali.

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post #6 of 12 Old 10-17-2011, 08:27 AM
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Relays are where it's at. You're wasting money trying to fit modern H4 bulbs and then turn around and feed em 11V thru the stock wires. The stockers would put out more light if they just had the full 13V available when the truck's running.

Ever driven a vehicle with a dying alternator and seen how dim the headlights are down around 10V? Same deal when you're only running 11.5 at the headlight but the truck's main harness has 13V available

Ten bucks and an hour once you get down to it. You don't have to put relays on the high beam side. Solder everything, no crimps. Crimps will corrode and drop voltage over time.

Once you've got full battery voltage at the back of the headlight, if they're not bright enough look into a quality sealed beam like a silverstar. There's nothing wrong with sealed beam technology, the main reason that OEMs use twist in bulbs is aerodynamics/styling, not light output.

Believe it or not, they'll last longer at 13V. When volts go up, amps go down. Amps are what creates heat in the filament and shortens life span.

I drive old cars around 8 months of the year, and lots of passengers comment about how my headlights are brighter than their 30 year newer cars........Relays.

good luck!
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post #7 of 12 Old 10-18-2011, 07:28 PM Thread Starter
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Thanks for the info! The relay explanation make sense...
Forgot to mention that a previous owner updated all wiring with a PAINLESS WIRING SYSTEM. So the wiring is relatively new... possibly within the last 5 or 6 years???
Would this make a difference?... or would I still need to go with larger guage wires and relays?

Also... any simple wiring diagrams/instructions, and relay info would be great!

'79 CJ7, stock 304v8, T150 3spd, Dana 30, AMC 20, Dana 20 T/C, Flowmaster 40 dual exhaust, 4"spring lift, 1-3/8"shackles, 35x12.50 Toyo A/T, 15x10 M/T Sidebitters, rear 1pc axles, Warn front bumper w/VR8000, custom 5" tube rear bumper, nerf bars, Tuffy (console, glove box, side rear speaker/storage boxes), new dash panel and Autometer gauges
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post #8 of 12 Old 10-18-2011, 07:31 PM
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Another thread to save in the favorites.
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post #9 of 12 Old 10-18-2011, 08:14 PM
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Here is a thread that JeepHammer posts some great diagrams.

Check it out!
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post #10 of 12 Old 10-19-2011, 08:44 AM
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Here's the rundown on relays

You can get nice ones out of wrecked cars but parts store $8 relays will do the job. OEM relays usually come with a nice bracket and wiring pigtail. Parts store relays can have problems with corrosion if you just use normal spade connectors (no pigtail) and drive thru a few winters.

Relay pin configurations are standardized. You may see 4 pins or 5, but the 5th pin is just an extra trigger if you want to trigger via switched ground instead of switched power. Google "bosch relay diagram" to learn more.

If you have access to a wiring supply house or catalog, you can get pigtails with brackets built in and use the relays found in late model fuseboxes.

One relay will do two headlights. High beams are optional if you don't use em much.

A relay is essentially a starter solenoid. Apply power to it's electromagnet, and it throws it's internal heavy duty switch. This means the relay itself needs to be grounded because it's an electrical device.

Put them on your radiator support as close to the headlights as possible.

Get power from wherever your + battery terminal goes and run a 10ga wire to the relay, cut your headlight + wire 6 inches back from the headlight and run it to the relay's + trigger post. Run the output wire from the relay back to your headlight, attach to the other side of that fresh cut. Don't forget to ground the relay back to it's mounting bracket. Done.

Headlights only use 4 of the 5 pins. Since the 5th pin is a ground trigger, it's good for things like electric fans that use a variable ground sender as a switch.

You may see the interior's electrical performance improve, now that the largest electrical consumer (headlights) have been removed from the interior's main power wire. And may avoid having to buy a new headlight switch if yours had high resistance causing dim lights.

Really, this is something every +20 year old car should have done. The benefit of taking the headlights off the interior loom is hard to overstate. After doing my first couple conversions, I went out and bought a box full of different styles of brackets and pigtails. Anymore they're a standard shop supply for anyone serious about driving old/custom vehicles.

happy jeepin!
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post #11 of 12 Old 10-20-2011, 01:09 PM
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I am reading what you guys are writing and you make sense on the upgrading wires and such , but pictures would help immensly how you do it, I am wanting better lighting for my Jeep especially since im having lots of work done to it , .I'd hate to have it destroyed by a deer or other creature i couldnt see

I was considering H4 conversion , but after reading your article would like to try upgrading my wires before it swap housings to get the most from my lights

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post #12 of 12 Old 10-20-2011, 02:22 PM
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Originally Posted by skizriz View Post
Another thread to save in the favorites.
How do you save to favorites?

Glenn R. Lever
Rochester, New York 14617-2012
My Web Site http://www.lever-family-racing.com

My restoration thread here on the Jeep forum
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