A question for those of you that have used 5.0 L motor and harness; do the headlights operate through a relay. All wiring diagrams I have for my '90 Crown Victoria donor, only show fused cct going to light sw, then dimmer switch. I would have thought the dual high beams would have required a relay ? Been working on the wiring for my 50; a slow process.

Tom

 

Hi Tom,

Unless you are trying to wire your truck solely to accomodate the arness, the headlights and how they are wired really have nothing to do with your engine. If you have stock headlights, then just use the stock headlight switch and that's all. Forget about the modern harness for accessories outside the engine electricical/charging system.

If you want to, look in my #2 gallery for wiring diagrams that are simple and generic. Send me a PM with your e-mail address and we can talk off line if you need ANY wiring help.

Julie!

 

Stock headlight switch was for a 6VDC system. I would use the headlight switch for the '90 harness if you have one, otherwise I would buy a headlight switch for a 12VDC system. I know chevy used a relay on my 1997 blazer headlight system and many vehicles use relays on headlights, elect fuel pumps, stereo amplifiers and elect radiator fans. Your choice, if the amp draw is high enough to you, use a relay. Less amp draw on switch, longer life. I've seen some switches burnt badly, but most never cause a problem. Many systems in recent years have a high amp draw. chuck

 

The headlight switches were a simple contact type pull switch. The "6VDC" switch in your truck will work for 12 VDC with no problems except the instrument light dimmer will not function properly if it has one. It's a rheostat and is voltage designed.

There is a tremendous difference in th egirth and quality of the early Ford switches as compared to hardware built today - much of it overseas. Also, in th eshift from 6 to 12 volt, your amperage being carried will be half to supply the same wattage to a peripheral at 12 volts. So, it's getting better not worse.

You can replace the 49 stock switch with one out of a 56. It did have the rheostat to dim the lights and was rated to do so at 12 volts. It is slightly (very slightly) different in external configuration, but, the pull stem is interchangeable with the 49 so your **** will be "Stock."

The only other switches you need to change out from the 6V to a 12V conversion are wiper switch (and you shouldn't have one because your stock wipers should be vacuum) and heater switch (if you have a heater installed). On the rest of the truck, just light bulbs, starter solenoid and horn relay (i'm assuming you carried all th enew engine electrical items withthe engine - alternator, ignition, etc.)

I guess if you want to use relays you can, but it's just another thing in the circuitry that isn't necessary that can cause problems (that's just my opinion). One of the many glories of these trucks was their basic functionality while being auster and simple.

J!

 

Did the CV use a stalk dimmer switch, or one on the floor? If it used a stalk, it likely used a relay to avoid running heavy wires up the column to the switch on the stalk.

Two high beams aren't that high a draw (15 amps?), but some quad-light setups turn on the high in addition to the low beams, which starts to add up to serious current.

 

thanks for all the input; since I plan on running my two stock headlights modified with late model sockets; I'll do a load test on the lights before install, based on your feedback. If load is excessive I'll opt for a relay. I plan on modifying front park lights to have signals working, haven't decided on style of socket for these yet. I do have the CV parts but they seem pretty cumbersome, requring large cutout to the stock park light housings. Any input welcome.

Later

Tom

 

If you mean you will be using standard sealed beams with a late model plug in socket then your switch should be adequate but be sure there is a self resetting circuit breaker in the line (headlights don't usually use fuses, if there is an electrical short, it's better to have lights that blink on and off than go out completely from a blown fuse). If you plan to use a conversion headlight housing with a seperate halogen bulb installed inside, then I would suggest using a relay. The current draw with halogen bulbs such as the H-4 is pretty high to run thru the switch. Here's a pretty good reference to using and chosing relays: http://adcmobile.com/appguides/BoschGuide.pdf

 

Tom, like this maybe? Any parts store or Cdn tire etc?




PS; Use all the relays you can, the more the better!!!!!!!!!!

 

You just need to swap the single filament bulb socket for a dual filament socket. Typically the stock sockets are swedged in, you may need to unbend them or grind the edge off to get them out of the housing. You can then replace them with something similar to the ones OF1 pictured. A couple of pop rivets or small sheet metal screws will hold the socket in place.

 

Thanks again; I am in the middle of re-wiring with donor harness. I won't get to the lights until new year now but will update once I do. As an aside; was there a firewall pass thru grommet for the dimmer switch, it seems this is a bad location as the terminations will be subjected to road moisture?

 

there is a website that advertises conversion kits for halogen headlight replacements that look stock, but I have not checked out the price.

reenmachine.com

Marc

 

The conversion kits consist of empty headlight housings with a socket for a halogen (H4 ?) bulb, a set of wiring pigtails and possibly a relay. They simply replace the sealed beam bulb. The prices vary quite a lot depending if the housings are all plastic, metal reflector with plastic lens, metal reflector with glass lens and how much the seller "loves" their product so shop around. I have seen prices from 80.00 to 200.00 a set. There are some that have an extra socket at the bottom for a turn indicator bulb and even some with a plastic glow ring around the edge that comes in different colors!

 

in the original crown vic harness there is only a relay if you have autolamps, the regular light circuit does not have a relay. i have the wiring diagrams saved in my gallery if you need them, i`m doing the same thing using the complete crown vic wiring harness, i`m also using the steering wheel assembly because it will elliminate most of my switches on the dash, i`ll just need one for the lights and thats it!