Topic: grounding fenders for lights


Wolfie    -- 07-24-2011 @ 5:23 PM
  My car has been painted and I'm about to put the fenders on. I've heard that you need some bare metal on the fender to bare metal on the body so that you have a proper ground for the lights to work. Many of you have been through this so what have you done?

Thanks!


supereal    -- 07-24-2011 @ 5:28 PM
  I don't depend on a body ground for any part of the system. Just an ohm or two at six volts will drain that part of the wiring. We run a separate ground wire to all parts, such as headlight and taillight housing, leading back to a known good ground, such as where the battery ground strap connects with the firewall or block. Years of rust, dirt, and paint render the body a poor ground, to say the least.

This message was edited by supereal on 7-24-11 @ 5:30 PM


joe b    -- 07-25-2011 @ 6:23 AM
  Super could you please go into a little detail for us electrically challenged? Do you mean that you run a wire the length of the car and then tap off it to each tail light for example. I have a right tail light on my '41 that is so dim you have to strike a match to see if it is working. I have taken the ground wire for this and scr*ped the paint off to get a better ground. I can't seem to find the problem.


TomO    -- 07-25-2011 @ 7:45 AM
  Wolfie, most cars do not need bare metal on the fender to body joint. The bolts do a good job of providing a ground connection. Use new bolts and you will not have a grounding problem for many years.

Joe B, Your right tail light problem could be corrosion in the socket, or corrosion in the bullet connectors in the crossover wire. If you have added a separate ground wire from the housing to the frame, you have eliminated the problem of the fender and housing ground.

If you have 1158 tail light bulbs, (tabs on bulb are aligned) you may have the bulb in upside down. If the bulb is in the socket correctly, with the lens removed, take a jumper wire and connect it between a ground source and the housing of the bulb. If there is no change in the intensity, the problem is low voltage.

Check the bulb to be sure it is a 6 volt (1154 or 1158).
Check to see that there is nor signs of rust or corrosion in the socket.
Clean and coat all bullet connectors with a corrosion inhibiting grease.
Make sure that all of the connections are tight and fully seated.

Tom


supereal    -- 07-25-2011 @ 8:55 AM
  Joe: We use #12 or #14 wire, usually green, the standard ground wire color, and fasten it directly to the light housing with a sheet metal screw and a star lockwasher. Other branches can be added as you work toward a master grounding point. That is, both tail/stop lights can run on the same line, as can both headlight housing, etc. I simply got fed up with trying to produce adequate grounds by scr*ping rust and paint, etc. No electrical savvy is needed to do this, but almost always it brings the lights, etc, back to life IF the socket contacts and the sh*ll are clean, too.


Wolfie    -- 07-25-2011 @ 8:24 PM
  It seems like just the bolts would be a poor ground. There is fresh paint, rubber gromets, and welting to interfere with a proper ground. I am using new bolts. I'll probably give it a try, but Super's recommendation of running a ground wire to the light housings would be easy to do if I run into problems.


TomO    -- 07-26-2011 @ 7:17 AM
  I usually install a star washer under one of the bolts for the headlight and taillight buckets. I checked the ground circuit on my headlights after putting it back together and there was .1 volt loss in the ground circuit. That is within the margin of error on my digital meter.

Rust can increase the ground resistance and that is a problem with modern cars here in the "Rust Belt".

To check out the ground circuit, connect your meter between the grounding connector on the headlight bulb or socket and the POS terminal of the battery. Turn on the lights and measure the voltage.

Tom


carguy    -- 07-26-2011 @ 7:42 AM
  Supereal, I really like your policy of not relying on body/chassis grounds for lights. I'm wondering how you run the green ground wires such that they don't stick out like sore thumbs.

I'm going to have all new harnesses made and having them include separate ground wires makes sense to me. Comments?

Bill Brown
'34 Cabriolet


supereal    -- 07-26-2011 @ 10:38 AM
  I run the ground wires on the underside of the top of the frame rail using "wire frame clips" we buy from C&G. You will find them on page 194 of their online catalog cgfordparts,com These are an item used by Ford when the cars were built. Having a running ground put in a new loom certainly makes sense to me, I think it should be a standard practice for old cars to have them available.


tbirdhandyman    -- 07-26-2011 @ 10:58 AM
  Hi Carguy, I use narly the same ground scheme as Super. I use #12 black wire in the old style wire loom, and as they are all run inside of the frame on my '41, they do not stick out. I make up a #10 wire from the firewall connection down onto a 1/4" hole in the frame just below the cowl. From there on the passenger side, I run a #12 back to the tail light assembly and terminate it on one of the mounting studs. I also run one up to the right headlight bucket, where I drill a hole for a 10-32 brass bolt (on the back side). Inside the bucket, I take the ground wire from the socket and attach it to the new 10-32 bolt. I jumper up to the parking lamp mounting bolt. I run a #12 from the bolt in the RH frame up over the transmission hump (on the '41's) there is a grove where the removeable floor pan attaches that the loom fits into that holds it in place and you can hardly see it. I terminate this #12 into a hole on the LH side. I then duplicate the drivers side lamps, plus run a ground up into the deck lid and fuel sender and then into the top motors so they run like sewing machines. Have your supplier supply wires for an electric fuel pump and turn signals and fog lamps. Then you have no extra wires exposed and it looks factory. This is a long post, but you wind up with very bright lights. I also opened up all of my NOS switches and removed the 70 year old crud that was on nearly every contact. Regards, Robert E.

Tbirdhandyman


EFV-8 Club Forum : https://www.earlyfordv8.org/forum
Topic: https://www.earlyfordv8.org/forum/viewmessages.cfm?Forum=18&Topic=3457