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Headlight Relay Harnesses

Started by Dan LeBlanc, April 15, 2017, 07:33:06 AM

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Dan LeBlanc

Has anyone tried the headlight relay harnesses?  Do they really work to brighten headlights?  I installed 4 halogen sealed beams in the 70 and light output is adequate, but could be a tad brighter. Yes, I know they're not correct but 2 of the 4 T3 reproductions that were in it died in short order. Couldn't justify another set of those. I just don't want to find out the hard way either that I've overloaded the headlight switch as well so I thought I'd see if anyone has any experience with the relay harnesses.

I've found some that are plug and play.
Dan LeBlanc
1977 Lincoln Continental Town Car

chrisntam

I too am looking at adding a harness that you reference,  This is the one I'm looking at:

https://ceautoelectricsupply.com/headlight-relay-kits/h4-sealed-beam-headlight-relay-kits/

Yes, this one is a little ($170) pricey...but it looks nice.

My only real issue is that I don't really drive it at night nor do I use the headlights during the day....

Which one(s) are you looking at?
1970 Deville Convertible 
Dallas, Texas

WTL

I assembled a relay harness from scratch last week for my OEM bulbs, and it really helped the bright beams, not much change for the low beam. 

My understanding is that halogen requires more juice, and might stress your stock wiring so you probably would be money ahead to go with a relay/ the headlight switch will love you for it, if nothing else.

Dan LeBlanc

I was thinking the same thing. I'm in a rural area and usually on the way back from being somewhere I end up in the dark. Lots of deer around. The more illumination, the better. I'm thinking the same way also - easing the load on the switch.

I was thinking something like this: http://www.ebay.com/itm/331686107210
Dan LeBlanc
1977 Lincoln Continental Town Car

The Tassie Devil(le)

Quote from: chrisntam on April 15, 2017, 10:04:46 AM
I too am looking at adding a harness that you reference,  This is the one I'm looking at:
https://ceautoelectricsupply.com/headlight-relay-kits/h4-sealed-beam-headlight-relay-kits/
Yes, this one is a little ($170) pricey...but it looks nice.......
Boy, that is horrendously expensive.

I installed my relays into my own cars using simple relays (one for high beam, and the other for low), wiring from the battery with an inline fuse to the relays, and the factory wiring to the light diverted to the relays for switching.

Actually cost me virtually nothing as I had Relays and wiring laying around.

I should have used circuit breakers and fusible links in the battery wiring, but that will come at some stage when I get around to it.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

bcroe

#5
I ordered a car with halogen headlights; didn't think they did anything else special. 
Halogens are probably more efficient; I should measure but I don't think the current
is much different. 

A couple relays are $5 on Eb+y, you can save a lot by doing your own wiring.  A fusible
link from the battery feed is a very good idea.  I'd run a test to see what is to be gained. 
With engine off, high beams on, connect your voltmeter between the battery positive
terminal and the bulb + terminal.  More than half a volt means there is room for some
improvement.  I would not feed direct from the alternator stud UNLESS the feedback
terminal is connected directly to it.  Alternator output through a marginal connection to
the battery could raise the stud voltage quite a bit to the point of shortening bulb life.   

The other voltage to check is between battery ground and the negative bulb terminal. 
This should be below 1/4 volt; otherwise you are loosing free power.  A relay won't
help this, but you can easily rework and optimize the ground circuit.  Bruce roe

cadman56

Many years ago I restored a 67 Eldorado.  At that time I published a chart in the SS I found from one of the major bulb manufactures.  I do not remember the exact current draw for the halogen sealed beams vs. the standard but it didn't seem too much different.  I just plugged in the halogens in place of the standard.
I did a lot of night driving with my 67 Eldorado for several years and experienced no wiring issues at all.  The only problem I encountered was the lights were so much brighter the auto dimming didn't work well
Maybe the lights are different from back then.
Fuseable links are a good idea and regular relays will work fine as others have mentioned.
Larry
1956 Cadillac Coupe deVille (sold)
1956 Cadillac Convertible (sold)
1956 Cadillac Eldorado Seville (sold)
1967 Cadillac Eldorado (sold)
1968 Cadillac Convertible (Sold)
1991 Cadillac Fleetwood Brougham dElegance
Larry Blanchard CLC #5820

Scot Minesinger

I installed halogen lights in my 1970 Cadillac and the illumination is just fine.  I never drive with bright lights on because it is a pain to dim when oncoming traffic arrives, which is frequently.  The auto dimmers are worthless now with street lights and curves in the road where I live.

We have a lot of deer.  In first six years hit 5 deer until I bought those noise makers you stick on.  Here is a tip for you to avoid deer in the head lights that saved me:  Lock em up.  Jam on the brakes when you might hit an animal while of course maintaining control - the screech noise breaks the deer in the headlights trance and they get out of the way.  ABS cars cannot do this.  This saved me from killing a beautiful German Shepard a few years ago.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

The Tassie Devil(le)

Can you claim flat-spotted tyres on insurance?

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe