Gold Lifetime Member
Join Date: Apr 1999
Location: Vancouver Island, Canada
Re: headlight woes
Just went through this nightmare myself and was surprised that in 90% of all instances it led back to grounds!
The first thing I did was setup a ground on the rad support above the battery using stainless steel bolt ,washers and lock washers on both sides under the washers.( Cleanup is IMPORTANT. Make sure you have clean metal and use electrical grease to help protect the metal! I ran a 10 gauge wire to this grounding point from the negative battery. I also ran another 10 gauge wire from this ground on the rad support to the fender and cleaned the underside with wire wheel to ensure clean contact. This point was secured with stainless steel fastener and Star lock washer (These will be your best friends). I also added another ground on the other side of the rad support above where the external voltage regulator is located using stainless steel hardware and Star Lock washers under washers. I ran a 10 gauge cable to the underside of the fender again wire wheel area.
I ran 1 gauge Negative battery cable to the front of the block again wire wheel contact point and star lock washer to ensure contact.
I added another 10 gauge wire from the fire wall ground straps on each side and ran these to the fenders where they bolt to the firewall, cleaning area thoroughly and using star lock washers.
I added another 10 gauge ground wire from block to chassis using star lock washers stainless bolts.
The reason was simply to ensure that I would have fewer headaches to worry about. Upon inspection of the previous grounds I found corrosion of wires, surface rust, and paint that would otherwise interfere in achieving any kind of a ground!
Back to light situation.
Having rewired my lights I did not get anything! Using a test light I was able to ascertain that I had power. The next logical step was to check and clean the electrical clips I was plugging into. Upon inspection these where badly oxidized so I cleaned them up and put electrical grease on these and reinstalled them. Still No Lights!
The next logical step would be the grounds for the lights on the rad support! After pulling these I noticed oxidation build up on the wire and fastener. The ground point on the radiator support had paint on it and there was no way this would make ground. Cleaned it to bare metal and added a star lock washer to it and sure enough the light work. Did the same to the other side and it too worked!
Still I had no parking lights!
I again made sure I had power going to the parking lights using a test light. Once that was confirmed I checked the bulbs! The driver side was burnt out but the passenger side was fine! I replaced the bulb and sure enough it worked for 5 seconds and then died.
Pulling the bulb showed it was fine? So I looked at the socket and saw it was badly oxidized. I cleaned it up added electrical grease and still nothing! Next thing was to check its ground on the inner fender. I cleaned it to bare metal added new stainless screw and star lock washer. Still Nothing!
Frustrated I pulled the whole parking light assembly! I cleaned the electrical contacts in the clips, washed the housing with degreaser and stuck it back in. Still nothing! I pulled it out again and inspected things. I noticed I had overlooked the backing plate bracket that secures the housing to the valance. I wire wheeled it and painted it seeing how I had it out!
I also wire wheeled the housing where this bracket touched at the base of the studs that secures it and also the round retainer clips that go on the studs. Before reinstalling the parking light I made sure that I had bare metal on the retaining bracket where it touches at the base of the housing and on the other side where the nuts make contact after they are tightened using electrical grease at these points to protect the bare metal.
I reinstalled the parking light and hit the switch and the darn thing lit up!
The moral here is do not overlook your grounds and assume that they are fine because things worked previously. Oxidation and corrosion can build up while things have been taken apart and are sitting waiting to be replaced. In just two days one ground spot I had prepped for wiring had surface rust appear when I went to wire it up. Get yourself some dialectic grease for your electrics and star washers and give yourself some peace of mind.
Oh... if you are still using the rear light sockets that pop out all the time and make poor contact in the housing buy yourself the metal Ford sockets and don't look back.
Those messing with gauges, add a seperate ground wire for the housing to fire wall and alleviate your headaches.
Those with rs headlight doors should be sure that the relays mounted on the rad support and headlight buckets do not have paint on ether of the mounting surface where they make contact. Use star washers on these and electrical grease on the bare metal also. You may find alot of your door opening and closing issues disapear.
Sorry for the long winded explanation.
67 RSSS Van Nuys, 4th week Sept,1966
ps,tilt,headrest,spd warn,pw,am/fm,delux int,
remote mirror,rear defrost,tint glass.etc...
TKO 600 Extreme,12bolt 3:73 gears.
Last edited by 67RSSS; Jun 14th, 10 at 03:37 PM.