86 f250 electrical problems

GT3FC

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hey y'all I know this is not a truck forum but I know many of the members are very knowledgeable about fords so I thought I'd give it a try. I just picked up a 1986 F250 with a 6.9L. While driving it home from work tonight I realized that every once in a while I would not get power to the radio, the clock in the dash, and also the windshield wipers would shut off, then they will come back on when i swerve or hit a bump. Sometimes they just randomly come back on. this leads me to believe its just a bad connection somewhere I'm guessing that these are all on the same circuit in some way or another or maybe powered by one of the two batteries? The terminals on both batteries are pretty gnarly. I plan to replace them on my next day off ( I hope its just a bad connection on one of the terminals) but assuming it is not does anyone have a wiring diagram of the circuits these are on or know where I can get one? also does anyone have any ideas to put me on the right track? I am pretty good with electrical work I plan on tracking the wires around and seeing if I can find anything loose.
 

CC'S95GT

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When you getting those terminal ends buy a Haynes manual too. there's wiring diagrams in the back.
It's very likely a lose wire under the dash.
 

ttocs

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start simple by removing, cleaning and reconnecting all battery connections and ground connections. After that take a pass over the fuses and make sure they are all good still. it sounds like you have a short though and being that it comes and goes it could be a royal pia to figure it out.
 
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GT3FC

GT3FC

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start simple by removing, cleaning and reconnecting all battery connections and ground connections. After that take a pass over the fuses and make sure they are all good still. it sounds like you have a short though and being that it comes and goes it could be a royal pia to figure it out.

I cleaned the terminals on the batteries tonight....one of the terminals on one of the batteries was so bad that some of the metal was eaten away by the corrosion.....we will see if that helps...I have a very strong suspicion that it was the one terminal mentioned above because it had horrible contact with the battery terminal....but I will still likley end up replacing all the fusable lnks with in line fuses and re running all the wiring in some heat resistant material....but all in all I am very happy with the truck!
 

ttocs

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its hard to say that a bad connection on the battery cable would cause JUST the pieces you mentioned to go on/off and not the whole vehicle but with that out of the way its one less thing to worry about. If you or anyone else has not heard you can simply use a cola/soda to clean the battery terminals as its acidic enough and the carbonation helps to loosen it all up and next time you are at harbor freight pick up one of these for the toolbox.
image_14907.jpg

Only costs a couple of bucks and makes cleaning the terminal on the battery and the car a 10 sec event.

If you suspect a bad connection on a cable the best way to test that theory is to just grab the area of the cables suspected and get a little rough with them. They should be able to take a really solid pull/tug on them with out a problem and by moving them around you can hope to make/see the short in front of you. Just look for ANY bare copper on the wires the smallest hole in the insulation/connection.
 
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GT3FC

GT3FC

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[video=youtube;ZAgS2OvFSq8]https://www.youtube.com/watch?v=ZAgS2OvFSq8&feature=youtu.be[/video] [MENTION=11896]ttocs[/MENTION]
I went out tonight to check over the insides of the dash and I noticed this
 

ttocs

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yup looks like a bad ignition switch from here. I know they are easy to replace on our mustangs I would imagine is probably the same design for your truck. There should be a hold underneath the colum that would look to have a screw in it but instead if you were to look in it you would see two small circles. Put the key in, turn it to on and then stick a pick or small tool inside the small circle in the middle and then you will be able to pull the entire key/cylinder straight out. You can have a locksmith switch the tumblers if you want to keep the original key in case it operates another lock on the truck but otherwise it comes with a new key.
 

ttocs

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maybe its not like our cars then as if it takes more then a few minutes on our cars then something is really wrong.
 
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GT3FC

GT3FC

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alright well i will have to take a look at it thanks everyone. ill put a new ignition switch in and see if that solved my problem.... i will be very happy if thats what it is.
 

uncltrvlnmatt

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I would do the complete ignition switch. Also check where the radio is powering up from. Sometimes with these old cars/trucks they don't or can't use the original wiring harness connections. They may have just run a hot wire to the fuse box and stuck a spade connector where one of the fuses are.
 

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