Electrical Fun
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Senior User
Joined: Aug 2012
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From: Corvallis, OR
Electrical Fun
Hey all,
So I decided to tackle my rear lights yesterday.
Starting condition: License plate light, right side reverse and tail lights not working, everything else working.
Finish condition: Entire right side not working except brake lights (side lamp, reverse, tail light) both license plates working.
I pulled the ground screw behind the taillights, cleaned it with WD40 (is that right) and then re installed it. Tried different bulbs, tried disconnecting/reconnecting. Even broke out the multimeter. When testing from the bullet connectors to the bumper as a ground I get some sort of voltage, but it is fluctuating and not constant. Should I dig somewhere deeper? The part that is getting me is that the brake lights still work.
Any suggestions would be great.
ADJ
So I decided to tackle my rear lights yesterday.
Starting condition: License plate light, right side reverse and tail lights not working, everything else working.
Finish condition: Entire right side not working except brake lights (side lamp, reverse, tail light) both license plates working.
I pulled the ground screw behind the taillights, cleaned it with WD40 (is that right) and then re installed it. Tried different bulbs, tried disconnecting/reconnecting. Even broke out the multimeter. When testing from the bullet connectors to the bumper as a ground I get some sort of voltage, but it is fluctuating and not constant. Should I dig somewhere deeper? The part that is getting me is that the brake lights still work.
Any suggestions would be great.
ADJ
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Sounds like you have ground issues. There are 4 wires going to the rear of your truck.
1- Backup, If one side works there is power there.
2- Tail, this will power both sides tail, license plate. If anything burns there is power.
3/4- Brake & left/right turn signal. With the switch on and the brake pedal mashed if one lights you have power. The signal shares the brakes and does have left & right.
Usually it is dirt & corrosion that stops them from working. Get an icepick looking circuit tester. When the clip is connected to the chassis any hot wire will light the bulb in the handle.
guluk
John
1- Backup, If one side works there is power there.
2- Tail, this will power both sides tail, license plate. If anything burns there is power.
3/4- Brake & left/right turn signal. With the switch on and the brake pedal mashed if one lights you have power. The signal shares the brakes and does have left & right.
Usually it is dirt & corrosion that stops them from working. Get an icepick looking circuit tester. When the clip is connected to the chassis any hot wire will light the bulb in the handle.
guluk
John
Hotshot
Joined: Mar 2013
Posts: 14,255
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From: Phoenix, Az.
I wouldn't have used WD-40. I'd use sandpaper. I don't remember the beginning. Did something happen or change just before the lights went hay-wire? (pun intended). If not,I'd keep following the wires forward with John's ice pick curcuit tester until you've got juice. There would be your problem.
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From: Corvallis, OR
Back to this,
Where are the grounds for the lights. I see a wire coming off of the side marker that is screwed into the sheet metal. I assume this is ground for the side marker. But the other bulbs only have one wire going into them. What should I be sandpapering/cleaning?
ADJ
Where are the grounds for the lights. I see a wire coming off of the side marker that is screwed into the sheet metal. I assume this is ground for the side marker. But the other bulbs only have one wire going into them. What should I be sandpapering/cleaning?
ADJ
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
ADJ, When you see a ground wire there is usually a gasket involved. Metal to metal contact to the body or chassis completes the ground back to the battery. Clean bulb ends, around areas where the screws are used. You are trying to get rid of grunge.
John
John
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
1967/72 F100/350 Styleside taillamps same as 1967/77 Bronco & 1969/74 Econoline.
Only gasket on F100/350's is between lens and lamp body.
Only gasket on F100/350's is between lens and lamp body.
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Fleet Owner
Joined: Jun 1999
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From: Creedmoor, North Carolina
I surely hope that you are not.
John
Ford Parts Specialist
Joined: Nov 2006
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From: Simi Valley, CA
Where is this gasket located you are speaking of, Mr. Wilker? Inquiring minds wanna know.
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
Back to this,
Where are the grounds for the lights. I see a wire coming off of the side marker that is screwed into the sheet metal. I assume this is ground for the side marker. But the other bulbs only have one wire going into them. What should I be sandpapering/cleaning?
ADJ
Mr. Wilson, PLEASE begin a thinking process, I understand you being an old fart, but with a good memory, so it could take a while for it to take hold.
We are not selling Ford truck parts on this site, we are responding mostly to truck owners with questions related to the truck they are working on/with at the time of the posting. Correctly so many times they need parts and that is where you shine brightest.
ADJ clearly stated that he sees a ground wire that is screwed to the sheet metal. As you well know a common ground method is used on these trucks. There has to be an interrupter aka a gasket between the appliance and the vehicle to require a go around wire.
John
Ford Parts Specialist
Joined: Nov 2006
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From: Simi Valley, CA
1969 F100/350 Stylesides from serial number F70,001, 1970/72 F100/350 Stylesides & 1970/74 Econolines:
There is no gasket associated with the quarter panel (bedside) marker lamps, not even between the lens (15A201) and body (15A440). Socket with lead wire swagged into metal body.
Truck parts catalog of F100/350 doesn't show a clear shot of these parts, so here's the Econoline pic. Parts are the same.
There is no gasket associated with the quarter panel (bedside) marker lamps, not even between the lens (15A201) and body (15A440). Socket with lead wire swagged into metal body.
Truck parts catalog of F100/350 doesn't show a clear shot of these parts, so here's the Econoline pic. Parts are the same.
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Senior User
Joined: Aug 2012
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From: Corvallis, OR
Figured it out guys,
The ground wire was for the side marker lamps, the rest of the bulbs were grounded by the screws that held the whole assembly in. Once I cleaned them off they started working again.
Thanks
The ground wire was for the side marker lamps, the rest of the bulbs were grounded by the screws that held the whole assembly in. Once I cleaned them off they started working again.
Thanks
Freshman User
Joined: Sep 2012
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And good job finding the problem! Now, next time you are at your local parts store, pick up a spray can of dielectric grease and hit your exposed electrical stuff with a squirt or two. It'll keep em from deteriorating so fast. Oh, and save the WD40 for nuts and bolts, it causes lots of issues with electrical circuits.
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