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Old 09-23-2006, 11:40 PM
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Adding a relay to the headlights

I took my 65 galaxie on its first long distance trip today to a car show and on the way home with the bright lights on for over 15 minutes the headlights went out,I have heard that halogens will overload the headlight switch and relays need to be added so has anyone done this to their older cars. Jeff

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Old 09-24-2006, 02:35 AM
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Doc here,

Yup...

Now you may have to replace the headlight switch or hi / low switch...before you can get it operable again..

THEN....

Get a set of relays..

Hook them as follows:
  • # 85 to the OLD headlamp power wire (under the hood to the headlamp) 12 0r 14 ga wire
  • #86 to a proper ground, 12 or 14 ga wire. burnish paint and use a star washer.
  • # 30 to the headlamp 10 gauge wire..
  • #87 to the battery positive terminal Via a proper fuse link, 10 gauge wire..



Do the same for the high beam circuit...

Next confirm you have proper grounds at the headlamps, and proper bonding, burnish paint and add starwashers...

That should give you a trouble free system..

Doc
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Old 09-24-2006, 09:53 AM
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I was lucky they came back on after shutting them off and turning back on but I never used the high beams again on the way back. Jeff
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Old 09-24-2006, 10:59 AM
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Many of the older Fords used a self-reseting breaker in the headlight circuit, so you wouldn't be left without headlights if there was an overload.

Probably the simplest solution is to add one of the headlight relay kits that are sold from several sources. Mad Electronics sells a generic relay kit, and LMC truck sells a kit that is specifically designed for headlight circuits.

The LMC truck headlight kit just plugs into your headlights (no wire cutting if you have standard three prong headlight plugs) and then connects the power directly to your battery. When you turn on the headlights your switch just activates the relay, and all the high-amperage flow goes directly from the battery to the lights. The kit costs about $30 from LMC.

Bruce
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Old 09-24-2006, 06:54 PM
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Doc here,

Depending on the Switch you installed with the new harness, you probably had a Thermal reset Circuit protection device Built internal the switch as 75GMCK25 Suggests, which may be why the Lights returned to service..

For Sure if it was stock switchgear, may NOT..So It would be a good thing to investigate , Prior to It leaving you stranded Somewhere on I~5 some dark moonless night..(from my been there , done that files..) Also check / Inspect the foot beam switch..

As for a Kit, several good ones are around..Don't really know what they get for them anymore...been that long since I bought one..(I build ANYTHING I need) ..

Here is the system I use on My DD Corvette...

  • The relay and socket base Cost me $6.49 At Rat Shack...
  • The 50 Foot roll of 10 gauge wire cost me about $4.00 at Ace Hardware in Bulk..
  • The 4 inch By 4 inch Aluminum bracket cost me nothing..scrap left over from a customer's job..
  • The Can of Plum Crazy Paint was left over from a Mopar Project..
  • The Misc. Hardware (Mount screws and Adel Strain relief at the business end of the relay, FUSE LINK, Fuse, Shrink tubing, Etc..) were all "Junkbox " Items..

The Triple "10 Gauge wire " was made by me, by cutting the wire runs 2/3 longer than the actual length required to make the runs (and will stand about 150 amps of abuse..) By inserting one set / End of three wires into a Bench Vise..The other end into a reversible drill motor..and spin it up until it starts to "Ball" up on itself..then back off a bit until straight (you need to keep it tight the whole time..)

You end up with a Nice looking , spun wire, that will hold more amps then you'll ever be using, that will resist collapsing magnetic fields and other noise generating sources.. somewhat..

The mount was made from a 4 foot piece of scrap aluminum..chopped a 4 x 4 piece off it..rounded off the ends with a bench grinder, beveled the edges, Laid out and cut the square hole for the relay socket base, (provided template with the Rat Shack relay), Drilled and countersunk mount holes, sanded with 150 then 220 Grit paper..primered, dried with a heat gun..the applied the plum crazy paint..also flashed with a heat gun..(about 25 seconds..)

Wired it into the car , under the hood , where the power runs to the lamps from the switch for the control, and to the battery for source current Via Fuse link..with ALL solder joints (NO BUTT SPLICES..they won't fit the triple 10's anyway..) and double heat shrink the joints..

Cost of The project...About $11.00...
Time Involved...about half a Saturday ..(in between watching Football games..)
Peace OF mind...Priceless...

Doc
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