Tail light issues

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Tail light issues

Tyler
I think I found my REAL problem.  It's not an amperage deficiency, requiring 3G but something else.

Backup lights never worked since I got the truck.  Switch on tranny replaced and still no workie workie.  Then, I removed the trailer wiring harness which was a plug-n-play splice at the tail light connector back by the bumper.  Reverse lights worked.  I celebrated.  I finished the Sniper install.

Now they don't again...  Also, when the headlight switch is on, tail lights are not, license plate lights are and brake lights do not energize when I step on the pedal.

When headlight switch is off, brake lights work.

When truck is put into reverse, the brake lights come on instead of the reverse lights.  I did not switch the bulbs into the wrong sockets, I promise!

138 days until I take a two month, 5,000 mile, one way, cross country trip

Combing the schematics but I'm a mechanic, not an electrician...
1985 F150 4x4 SB 300 I6: Comp 268 cam, '68 240 head, Offy DP, FI manifolds, Holley Sniper 2300, DUI street/strip distributor, BW T-18, Tuff Country 4" suspension lift, Yukon Offroad hubs + front and rear Duragrip LSD 3.73 ratio, 33-12.5/15s

Gear Vendors overdrive unit on order.

Oklahoma boy livin in Washington State.  Retired submarine MMNCM (Nuclear Machinist's Mate, Master Chief)
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Re: Tail light issues

old55pete
Sounds like you have a ground issue. Like all of the lights are grounding through each other to come on. At the back of the frame in the harness there should be a Black wire with a white stripe, strip some of the insulation and add a temp ground to the frame and see if the lights work correctly.
Steve
86 Bronco, XLT, 5.0 EFI, EEC IV, AOD, IFS, limited slip front and rear, 3.08 gears, Tilt steering, factory AC
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Re: Tail light issues

Tyler
Will do.

Also, my hazards work until I put the key in run and the transmission into reverse.
1985 F150 4x4 SB 300 I6: Comp 268 cam, '68 240 head, Offy DP, FI manifolds, Holley Sniper 2300, DUI street/strip distributor, BW T-18, Tuff Country 4" suspension lift, Yukon Offroad hubs + front and rear Duragrip LSD 3.73 ratio, 33-12.5/15s

Gear Vendors overdrive unit on order.

Oklahoma boy livin in Washington State.  Retired submarine MMNCM (Nuclear Machinist's Mate, Master Chief)
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Re: Tail light issues

old55pete
I am assuming that is because they are loosing their ground.
Steve
86 Bronco, XLT, 5.0 EFI, EEC IV, AOD, IFS, limited slip front and rear, 3.08 gears, Tilt steering, factory AC
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Re: Tail light issues

grumpin
I’ve had 2 or 3 trucks that I had to redo the trailer lighting on. On my 86 I had problems with the ground as Steve said. Can’t remember what exactly it was doing.
Dane
1986 F250HD SC XLT Lariat 4x4 460 C6-Sold
1992 Bronco XLT 4x4 351W E4OD
1998 GMC Sierra SLE K1500 350 4L60E
Arizona
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Re: Tail light issues

Gary Lewis
Administrator
Yep, I agree.  Electrical problems that make no sense, at first blush, are almost always a ground problem.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

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Re: Tail light issues

FuzzFace2
I see you have a 300 six and the ground cable from battery run along the top of the frame with a tab grounding the frame and then on to the top starter bolt.
I would remove that bolt and clean the frame & tab and bolt it back down and see what you have.

What bed does the truck have?
I forgot the year but the early trucks did not have a ground wire in the frame harness like the documents show going up to the firewall behind the radio.
The style side had a ground wire at each tail light and screwed to the bed behind the lights.

I don't know what the flare sides had but I ran a ground from each light, plastic housing, thing to 1 of the light housing bolts as the bracket is metal and bolted to the metal bed side panels.
Now my bed floor is a custom ribbed metal floor so the bed sides are grounded to it and the floor to the frame.
I have not had any issues with rear lights and I have 1 of them Tee's for trailer lights between frame harness and tail light harness.

I am with others it a ground issue.
Dave ----
Dave G.
81 F100 flare side 300 six / AA OD / NP435 / 2.75 gear
http://cars.grantskingdom1.com/index.php/1980-Ford-F100?page=1
81 F100 style side 300 six/SROD parts truck -RIP
http://cars.grantskingdom1.com/index.php/1981-Ford-F100
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Re: Tail light issues

Tyler
Thank you, All !

I don't know what I would have done without all of you helping me through.  I'm extremely grateful to have found this site.

Ground issue indeed.
I took the ground (black / wht stripe) wire and stripped a small section, then made a jumper with alligator clips and grounded it to the frame.
 
All lights work normally, now. Just need to finalize the new ground wire properly.

I'll go ahead and clean up the frame ground under the hood as recommended.  
1985 F150 4x4 SB 300 I6: Comp 268 cam, '68 240 head, Offy DP, FI manifolds, Holley Sniper 2300, DUI street/strip distributor, BW T-18, Tuff Country 4" suspension lift, Yukon Offroad hubs + front and rear Duragrip LSD 3.73 ratio, 33-12.5/15s

Gear Vendors overdrive unit on order.

Oklahoma boy livin in Washington State.  Retired submarine MMNCM (Nuclear Machinist's Mate, Master Chief)
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Re: Tail light issues

Gary Lewis
Administrator
Glad it worked, Ty.  

On your truck that wire should go back to a ground to the firewall ahead of the radio.  You might check that it is in place.

And then check that there is a ground wire from the back of the engine to the firewall close to if not on the windshield wiper motor.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

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Re: Tail light issues

Tyler
I just started it up and backed out of the garage.  Now having same issues with ground wire in place.  I wire wheeled down to bare metal before I put the ground in place.

Shaking my head...

I'll check the other things you mentioned.

On Sat, Jan 16, 2021, 8:21 AM Gary Lewis [via Bullnose Enthusiasts Forum] <[hidden email]> wrote:
Glad it worked, Ty.  

On your truck that wire should go back to a ground to the firewall ahead of the radio.  You might check that it is in place.

And then check that there is a ground wire from the back of the engine to the firewall close to if not on the windshield wiper motor.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI




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NAML
1985 F150 4x4 SB 300 I6: Comp 268 cam, '68 240 head, Offy DP, FI manifolds, Holley Sniper 2300, DUI street/strip distributor, BW T-18, Tuff Country 4" suspension lift, Yukon Offroad hubs + front and rear Duragrip LSD 3.73 ratio, 33-12.5/15s

Gear Vendors overdrive unit on order.

Oklahoma boy livin in Washington State.  Retired submarine MMNCM (Nuclear Machinist's Mate, Master Chief)
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Re: Tail light issues

Gary Lewis
Administrator
That sounds like you have a flakey connection somewhere that quit when the truck was moved.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

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Re: Tail light issues

old55pete
There is a ground tab on the ground from the battery to the engine. The tab bolts in the frame on the crossmember by the motor mount. Check it and see if it is there as that is the ONLY battery to chassie ground. If it is there, it might need to be cleaned. If it is not there, it needs to be.
Steve
86 Bronco, XLT, 5.0 EFI, EEC IV, AOD, IFS, limited slip front and rear, 3.08 gears, Tilt steering, factory AC
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Re: Tail light issues

Tyler
Thanks.  Yes, that one is definitely there, freshly wire wheeled and lugs cleaned.

I found a tail light bulb that was most likely shorted based on the glass twisting freely in the metal socket.  Replaced.

Also, picking up a new turn signal switch in a couple of hours.  Old one already removed.  Looked pretty worn.  I checked the flasher relay and it worked.

Had a blown fuse.  Still looking for any wires that have shorted.

On Sat, Jan 16, 2021, 1:40 PM old55pete [via Bullnose Enthusiasts Forum] <[hidden email]> wrote:
There is a ground tab on the ground from the battery to the engine. The tab bolts in the frame on the crossmember by the motor mount. Check it and see if it is there as that is the ONLY battery to chassie ground. If it is there, it might need to be cleaned. If it is not there, it needs to be.
Steve
86 Bronco, XLT, 5.0 EFI, EEC IV, AOD, IFS, limited slip front and rear, 3.08 gears, Tilt steering, factory AC



If you reply to this email, your message will be added to the discussion below:
http://forum.garysgaragemahal.com/Tail-light-issues-tp85198p85562.html
To unsubscribe from Tail light issues, click here.
NAML
1985 F150 4x4 SB 300 I6: Comp 268 cam, '68 240 head, Offy DP, FI manifolds, Holley Sniper 2300, DUI street/strip distributor, BW T-18, Tuff Country 4" suspension lift, Yukon Offroad hubs + front and rear Duragrip LSD 3.73 ratio, 33-12.5/15s

Gear Vendors overdrive unit on order.

Oklahoma boy livin in Washington State.  Retired submarine MMNCM (Nuclear Machinist's Mate, Master Chief)
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Re: Tail light issues

Tyler
Ok, final post for closure.  Everything works and better than ever.

I removed, cleaned and tightened the ground to frame under the hood as well as the ground to body behind the radio.  Cut out and replaced every wire splice behind the dash from POs using good quality heat shrink butt connectors.   There were many.  Capped off 2 hot wires back there and organized the rats nest using zip ties like I should have done the first time I opened up the dash two years ago.
Replaced the turn signal module in the steering column.   Found 2 PO taps into this wiring harness...
The OEM connectors for the reverse light and the rear lights were disassembled, cleaned and a small amount of dielectric grease added.
Replaced rear taillight bulbs (one was shorted to itself and the glass was freely spinning).
The main solid black wire ground connector (which feeds back to the dash) that is with the taillight connector was visibly deranged from overheating but had indication that it was a good connection.   So I replaced it with a nice waterproof aftermarket one anyway.

Removed any custom grounds that I put in.

Again, thanks for the help and crowd support.   I learned a lot and the electric schematic diagrams in the documentation section are excellent.

On to the next thing...
1985 F150 4x4 SB 300 I6: Comp 268 cam, '68 240 head, Offy DP, FI manifolds, Holley Sniper 2300, DUI street/strip distributor, BW T-18, Tuff Country 4" suspension lift, Yukon Offroad hubs + front and rear Duragrip LSD 3.73 ratio, 33-12.5/15s

Gear Vendors overdrive unit on order.

Oklahoma boy livin in Washington State.  Retired submarine MMNCM (Nuclear Machinist's Mate, Master Chief)
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Re: Tail light issues

Gary Lewis
Administrator
Excellent!  
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

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Re: Tail light issues

old55pete
Tyler, thank you for adding in the internaly shorted light bulb. I used to deal with them alot in the past as I am a semi mechanic. I will have to admit that the shorted bulb went over my head because semi's have mostly gone to led lights and and that never shows up. thanks for the reminder.
Steve
86 Bronco, XLT, 5.0 EFI, EEC IV, AOD, IFS, limited slip front and rear, 3.08 gears, Tilt steering, factory AC