84 F250 Electrical Problems
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84 F250 Electrical Problems
Desperate cry for help!
i have a 84 f250 with inline 6 engine 2 wheel drive.
problems:
1. No brake lights.
2. No rear running lights.
3. Left headlight does not work in low beam, only high beam.
Already tried:
1. replaced headlight switch
2. Replaced Dimmer switch
3. Replaced Turn signal switch
4. Replaced both headlights
5. Replaced all bulbs (side lights, turn signals, brake, rear)
6. I have all connectors for headlights and bulbs) but haven't replaced them all yet.
good news:
1. Turn signals & hazards work in front and rear perfectly.
2. Right headlight works and dims accordingly with dimmer switch.
3. I tested for a short by touching battery terminal and watching light bulb with a volt light (not sure what it's called) and from what I could tell the test told me I did NOT have a short.
What are your initial thoughts on the causes of problems 1-3?
Thank you in advance for your help!!!!
-FordFunRun
i have a 84 f250 with inline 6 engine 2 wheel drive.
problems:
1. No brake lights.
2. No rear running lights.
3. Left headlight does not work in low beam, only high beam.
Already tried:
1. replaced headlight switch
2. Replaced Dimmer switch
3. Replaced Turn signal switch
4. Replaced both headlights
5. Replaced all bulbs (side lights, turn signals, brake, rear)
6. I have all connectors for headlights and bulbs) but haven't replaced them all yet.
good news:
1. Turn signals & hazards work in front and rear perfectly.
2. Right headlight works and dims accordingly with dimmer switch.
3. I tested for a short by touching battery terminal and watching light bulb with a volt light (not sure what it's called) and from what I could tell the test told me I did NOT have a short.
What are your initial thoughts on the causes of problems 1-3?
Thank you in advance for your help!!!!
-FordFunRun
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Joined: Nov 2015
Posts: 30,870
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From: Angier, NC
Ok break out the test light as you got some testing to do.
Lets start with the head light. With test light test for voltage on each of the lights connector. 1 should be low beam, 1 high beam and the last ground.
If you have power to 2 of the 3 then I would say bad new bulb.
You checked ALL fuses if they are good?
Brake lights start at brake light switch. You should have power to 1 side all the time. The other side only when the pedal is pushed. If no power out replace the switch.
If you have power out of switch then check the turn signal switch.
Rear tail lights and maybe the cause of no turn/brake lights.
There is a harness plug (at least on my 81) below the master at frame rail/fire wall area. I am thinking you have a bad connection and why no lights out back.
If you have lights at that plug you then need to start looking from that point on back for bad wires.
Dave ----
Lets start with the head light. With test light test for voltage on each of the lights connector. 1 should be low beam, 1 high beam and the last ground.
If you have power to 2 of the 3 then I would say bad new bulb.
You checked ALL fuses if they are good?
Brake lights start at brake light switch. You should have power to 1 side all the time. The other side only when the pedal is pushed. If no power out replace the switch.
If you have power out of switch then check the turn signal switch.
Rear tail lights and maybe the cause of no turn/brake lights.
There is a harness plug (at least on my 81) below the master at frame rail/fire wall area. I am thinking you have a bad connection and why no lights out back.
If you have lights at that plug you then need to start looking from that point on back for bad wires.
Dave ----
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From: Virginia
Like was said, your brake light problem is going to be up front at the brake pedal switch or the turnsignal switch. The brake lights use the same wires and bulb filaments as the rear turns, so since your rear turns work, that means the wires and the bulbs to the rear are good.
Do your rear license plate lights work? They use the same wire as the rear marker/running lights.
Do your rear license plate lights work? They use the same wire as the rear marker/running lights.
FTE Legend
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From: Angier, NC
My bad I missed the turn lights worked so yes thinking brake light switch more now than turn signal switch.
Head light a bad plug/connection or bad bulb.
Good call on the plate light. If working then need to check the wiring to each light.
Any way he looks at it he is spending time with a test light lol
Dave ----
Head light a bad plug/connection or bad bulb.
Good call on the plate light. If working then need to check the wiring to each light.
Any way he looks at it he is spending time with a test light lol
Dave ----
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Dave and Franklin2,
thank you very kindly for your help!!
Possible Solutions: replacing the brake light switch and headlight connector.
Answer to your question: No, the lights to the rear license plate do NOT work. Thoughts?
Does this his look like the right part for brake light switch?
https://m.advanceautoparts.com/p/bwd-stoplight-switch-connector-pt235/20974568-P?searchTerm=brake+light+switch
thank you you again for your help!!!!
-FordFunRun
thank you very kindly for your help!!
Possible Solutions: replacing the brake light switch and headlight connector.
Answer to your question: No, the lights to the rear license plate do NOT work. Thoughts?
Does this his look like the right part for brake light switch?
https://m.advanceautoparts.com/p/bwd-stoplight-switch-connector-pt235/20974568-P?searchTerm=brake+light+switch
thank you you again for your help!!!!
-FordFunRun
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Joined: Jan 2001
Posts: 3,789
Likes: 26
From: Connecticut
Don't forget the rest of the system... bad ground = open circuit, "no workie"
Check all grounds. remove them and reinstall to make good connection, (adding a few from body, bed, body cab to frame, Frame directly to neg post will only help!
Check all grounds. remove them and reinstall to make good connection, (adding a few from body, bed, body cab to frame, Frame directly to neg post will only help!
FTE Legend
Joined: Nov 2015
Posts: 30,870
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From: Angier, NC
Dave and Franklin2,
thank you very kindly for your help!!
Possible Solutions: replacing the brake light switch and headlight connector.
Answer to your question: No, the lights to the rear license plate do NOT work. Thoughts?
Does this his look like the right part for brake light switch?
https://m.advanceautoparts.com/p/bwd...e+light+switch
thank you you again for your help!!!!
-FordFunRun
thank you very kindly for your help!!
Possible Solutions: replacing the brake light switch and headlight connector.
Answer to your question: No, the lights to the rear license plate do NOT work. Thoughts?
Does this his look like the right part for brake light switch?
https://m.advanceautoparts.com/p/bwd...e+light+switch
thank you you again for your help!!!!
-FordFunRun
You want the brake light switch Search Results for: brake light switch | AutoZone.com light switch
If you have no tail/running lights to the rear you are going to need to test where the power starts/stops starting at the lights and work forward.
As I think I posted there is a connector joining the front & rear harness at the floor board/frame rail could look for power to the rear at that point.
I thought you replaced the head light switch? If so yes it could be bad out of the box but if you have power to the other head light so I say the head light switch is good and it is the light connector.
Dorman Headlight Connector 85810 - Read Reviews on Dorman #85810
Could this be the cause of the rear lights not working? Yes but with out testing the wires who knows? Same goes for the head light connector.
Dave ----
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From: Virginia
The headlight switch and it's connector are common to the front and the rear lights. And also the headlights have just one common wire leaving the switch.
So if your front running lights are working, it's not the headlight switch or connector.
If even one of your headlights are working, low beam or high beam, then that part of the headlight switch and it's connector are good also.
There is a single wire leaving the switch for the headlights. It runs down to the floor to the dimmer switch were high beam or low beam are selected.
You have one single wire leaving the dimmer switch for low beam, and one single wire leaving the dimmer for high beam. So if one lowbeam is working, the dimmer is working. If one highbeam is working, then that also points to the dimmer switch working.
So if your front running lights are working, it's not the headlight switch or connector.
If even one of your headlights are working, low beam or high beam, then that part of the headlight switch and it's connector are good also.
There is a single wire leaving the switch for the headlights. It runs down to the floor to the dimmer switch were high beam or low beam are selected.
You have one single wire leaving the dimmer switch for low beam, and one single wire leaving the dimmer for high beam. So if one lowbeam is working, the dimmer is working. If one highbeam is working, then that also points to the dimmer switch working.
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From: Angier, NC
The headlight switch and it's connector are common to the front and the rear lights. And also the headlights have just one common wire leaving the switch.
So if your front running lights are working, it's not the headlight switch or connector.
If even one of your headlights are working, low beam or high beam, then that part of the headlight switch and it's connector are good also.
There is a single wire leaving the switch for the headlights. It runs down to the floor to the dimmer switch were high beam or low beam are selected.
You have one single wire leaving the dimmer switch for low beam, and one single wire leaving the dimmer for high beam. So if one lowbeam is working, the dimmer is working. If one highbeam is working, then that also points to the dimmer switch working.
So if your front running lights are working, it's not the headlight switch or connector.
If even one of your headlights are working, low beam or high beam, then that part of the headlight switch and it's connector are good also.
There is a single wire leaving the switch for the headlights. It runs down to the floor to the dimmer switch were high beam or low beam are selected.
You have one single wire leaving the dimmer switch for low beam, and one single wire leaving the dimmer for high beam. So if one lowbeam is working, the dimmer is working. If one highbeam is working, then that also points to the dimmer switch working.
I did know about the head light wire going to the dimmer switch and out to the head lights and why I say either bad (new) bulb or bad connector, guess the wire to that light could also be bad?
Dave ----
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UPDATE:
Thank you again Fuzzface2 and Franklin2 for your help!!!
Headlights: FIXED. The solution was the new connector. Now both headlights work
perfectly.
Brake lights: FIXED (sort-of). The brake light switch was installed and now the brake
lights illuminate when the pedal is pushed. However when
the lights are ON, the brake lights do NOT illuminate.
Continued Problems:
Running rear lights: Do NOT illuminate at any time.
Back-up lights: Do NOT illuminate at any time except my wife said they tried to
illuminate sort of when the lights were turned OFF.
Brake-lights: Do NOT illuminate when the lights are turned ON.
License plate lights: Do NOT illuminate at anytime.
Hopefully soon I'll have time to get my tester out and start testing. I double checked al the fuses and they are all good.
Your thoughts on these problems?
Thanks again!!
-FordFunRun
Thank you again Fuzzface2 and Franklin2 for your help!!!
Headlights: FIXED. The solution was the new connector. Now both headlights work
perfectly.
Brake lights: FIXED (sort-of). The brake light switch was installed and now the brake
lights illuminate when the pedal is pushed. However when
the lights are ON, the brake lights do NOT illuminate.
Continued Problems:
Running rear lights: Do NOT illuminate at any time.
Back-up lights: Do NOT illuminate at any time except my wife said they tried to
illuminate sort of when the lights were turned OFF.
Brake-lights: Do NOT illuminate when the lights are turned ON.
License plate lights: Do NOT illuminate at anytime.
Hopefully soon I'll have time to get my tester out and start testing. I double checked al the fuses and they are all good.
Your thoughts on these problems?
Thanks again!!
-FordFunRun
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Joined: Nov 2007
Posts: 22,415
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From: Denver Metro Area, CO
Rear running lamps, front running lamps, overhead lamps (if equipped), license plate illumination...
Are all one circuit, uses a Dark Brown (DB) wire that extends around the entire vehicle.
Your job is to find the problem in that circuit.
Are all one circuit, uses a Dark Brown (DB) wire that extends around the entire vehicle.
Your job is to find the problem in that circuit.
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From: Virginia
Lights in the rear not working when other lights are turned on means you have a grounding problem to the rear bulbs. If you want to test this theory, take the socket out if the housing. Leave the bulb in place, take a long piece of scrap wire hook one end to the bat neg terminal. Strip the other end and jam it down beside the bulb so it touches the brass part of the bulb. If that fixes your problem then you know its bad grounding
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