headlight relays

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737jetdr

737jetdr

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I just switched my 66 Cuda headlight wiring over to relays and what a difference it makes. I picked up 2 bosch relays,2 pigtails to plug them into and a fuse holder for about $35.00. It took about 2 hours to do. Before I changed the wiring, with my engine running my charging system was showing about 13 volts. When I turned on my headlights the voltage was dropping down to about 10.5 volts and the lights were a little dim. Now when I turn on the headlights you can't even see a voltage drop and the lights are full bright. I unwrapped my harness right behind the back of the battery and cut the low beam and high beam wires. Then I ran them under both ends of the battery tray and mounted my relays there. I posted a copy of the wiring diagram I used. Don't go by the wire colors on the diagram as the car wires are different. I highly recommend this mod. I am going to do my Dart next week.

cudaheadlights.jpg
 
............Good job............every1 should do it........every fuel pump and fan should use relays .....kim............
 
yep. well worth the time. everyone always asks me how i got my headlights so bright. and when i start to explain that i put relays in and try to tell them about voltage drop, their eyes just start to glaze over. haha
 
it doesnt say how many amps it is. if its just 30 or 40, then im goin to make my own connector and such, i dont want to spend $50, when i can pretty much do the same thing for for $14
 
I'm interested in doing this to my 66 Barracuda. Did you just splice the new relays wires into the old headlight wires, or run new wires form the relays to the headlight socket. If new wires, what gauge wire did you use?
 
Correct you are on the big difference on brightness! I had mine done this past Spring.
A buddy of mine did it for me.
It took him no time at all,and it only cost me about the same.
I did have to spring for the Beer!! I think it's a great idea to do.. Craig.
 
And add these Bosch headlights with H4 bulbs.
I plan on adding the relays as well, but as they are now, these headlights are brighter than my daily driver's headlights and they do not draw power away from my other lights.
slant6dan recommended.
 

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Gonna have to do that to mine when I get a chance, thanks for sharing the info.
 
I did this upgrade a while back. Excellent upgrade for small the amount of time/money involved.
There's a Bosch relay # 0 332 019 150, that might be a better choice than the one in the diagram. It has a second #87 terminal, rather than the unused #87a terminal. So you can run a wire from each terminal to its own lamp rather than splitting the wire after the relay.
 
I'm interested in doing this to my 66 Barracuda. Did you just splice the new relays wires into the old headlight wires, or run new wires form the relays to the headlight socket. If new wires, what gauge wire did you use?
 
If you want to do this and not cut anything, painless has been making these harnesses for years. The also come with weathpacked connectors..
 
GMachineDartGT said:
If you want to do this and not cut anything, painless has been making these harnesses for years. The also come with weathpacked connectors..
Click to expand...

is this one it?
http://www.painlessperformance.com/webcatalog/largeview.php?SearchField=30815&SearchAll=Classic%20Cars
 
dusterglenn said:
I did this upgrade a while back. Excellent upgrade for small the amount of time/money involved.
There's a Bosch relay # 0 332 019 150, that might be a better choice than the one in the diagram. It has a second #87 terminal, rather than the unused #87a terminal. So you can run a wire from each terminal to its own lamp rather than splitting the wire after the relay.
Click to expand...

50 amp version of this is Bosch relay # [FONT=Arial, Helvetica, sans-serif]0 332 209 138[/FONT]
diagram for double 87 pin out 30 amp
http://www.texasindustrialelectric.com/relays_0332019150.asp
 
The headlamp relay kit from Painless Wiring is a painful $168. You can buy relays and wired bases (4 term) cheap on ebay, but must wait on delivery from Hong Kong.

I went whole hog and got a Power Distribution Center (PDC) from a Grand Cherokee at the junkyard. Was maybe $20 and included the relays (7) and fuses. I thought I could leverage a lot of the wiring, but ended up taking out all the terminals and starting from scratch. I was 1 relay short (a future fan). Anyway, those are often a separate high-amp solid-state relay on many cars (bumper mounted), so I'll do that. Installing the engine harness currently and repairing the under-dash harness on the bench. I'll post a summary when done.

A basic "roll your own" 6-relay block from Painless is $291. A full PDC and wiring for an LS1 engine is $1600, which is closer to my effort. I don't see anything for Mopar.
 
you could wire those 2 relays together to a switch and have high and low at the same time.......super bright lights

a 90 to 93 toyota corolla has a relay box with 5 large relays in it...no fuses
 
glhx said:
you could wire those 2 relays together to a switch and have high and low at the same time.......super bright lights
Click to expand...

going to need something bigger than the foot dimmer, maybe one of these on the dash?

Mad-Scientist-Light-Switches-Industrial-Novelty-davesgeekyideas-2011.png
 
I made this headlight modification on the ‘67 Dart this spring using new sockets,and 12 gage wire from relays to headlights including their grounds powered from alternator power lug using Dan’s parts. It made a huge difference, not only in brighter lights, but significantly reducing power load passing through bulkhead connector, amp gage, and headlight switch. Using thicker gage wire lessens voltage drop, and heat build-up found with the factory 16 gage conductors caused.

I did not stop with lighting, relays are also powering electric choke, o2 sensor, and soon charging circuit employing remote voltage reading. The only high draw device left utilizing bulkhead connector is convertible top hydraulic pump which also uses two relays to take the load off of dash one year only switch.

I had a few questions early on concerning design, and /6Dan graciously guided me through with clear instructions. This is a great low budget improvement, but don’t use cheap relays not rated for higher under hood temperatures and harsh conditions. Spend a few more bucks for quality parts, and do it once right.

Currently I am rerouting conductors & relays for cleaner under hood look. Also I have installed a ‘sub panel’ if you will, to distribute fused power to all the relays in under hood area which also consolidates grounding conductors & feeds for a nice clean look
 
glhx said:
you could wire those 2 relays together to a switch and have high and low at the same time.......super bright lights
Click to expand...

This isn't a good idea if, like most of our cars, your high and low beams are produced by the same bulb. You throw a 100% overload on the common ground path of the two filaments, and you risk grenading the bulb with enough force to destroy the headlight reflector and lens. The bulb is pressurized to about 10 atmospheres cold. Internal pressure goes (way) up when it's hot, and if you now come along and throw 200% of the expected heat at it because both filaments are operating at the same time, you're playin' with fire.

If you have a car that produces the low and high beams with separate single-filament bulbs, you can safely do this as long as you make sure all the wiring's up to the task -- feeds and grounds alike.
 
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