BARRYS83F100 Posted September 20, 2020 Share Posted September 20, 2020 Next on my list is to add factory tachometer to my 1983 F100 5.0 auto, single fuel tank what years are the correct under dash harness can I use ? mine has to be converted as it has warning lights I am thinking 82,83,84 am I correct ? I have instrument cluster. thoughts ? Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 20, 2020 Share Posted September 20, 2020 Before we get to any specifics, make sure you want to do this. You do know that you have a 14-pin harness and you'll need the 18-pin harness. Right? If so, you can use any 1982 - 86 harness for a truck with gauges. And, you can use a 1980 harness for a truck with gauges but some of them will have to have some of the wires moved in the connector, which is easily done. Does that help? Link to comment Share on other sites More sharing options...
BARRYS83F100 Posted September 20, 2020 Author Share Posted September 20, 2020 Before we get to any specifics, make sure you want to do this. You do know that you have a 14-pin harness and you'll need the 18-pin harness. Right? If so, you can use any 1982 - 86 harness for a truck with gauges. And, you can use a 1980 harness for a truck with gauges but some of them will have to have some of the wires moved in the connector, which is easily done. Does that help? yes that is why i am asking so i can round up what i need to do install correctly anything else i am gong to need ? Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 21, 2020 Share Posted September 21, 2020 yes that is why i am asking so i can round up what i need to do install correctly anything else i am gong to need ? I've not done it, but I think you just need the dash harness. But, bear in mind that the function of the fuel tank switch changed over time, as did the speed control wiring. So if you have dual tanks or speed control you want to stay as close as possible to your year. Link to comment Share on other sites More sharing options...
BARRYS83F100 Posted September 22, 2020 Author Share Posted September 22, 2020 I've not done it, but I think you just need the dash harness. But, bear in mind that the function of the fuel tank switch changed over time, as did the speed control wiring. So if you have dual tanks or speed control you want to stay as close as possible to your year. any other changes ? under hood harness the same. feel free to chime in I want to have everything needed when I do conversion so I can finish. Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 22, 2020 Share Posted September 22, 2020 any other changes ? under hood harness the same. feel free to chime in I want to have everything needed when I do conversion so I can finish. There are several "underhood harnesses". Each engine has a different harness because of where the sending units are. And then there is the difference in ignition systems, fuel systems, etc. I guess I've lost track of what you are trying to do. Can you help me? Link to comment Share on other sites More sharing options...
FuzzFace2 Posted September 25, 2020 Share Posted September 25, 2020 There are several "underhood harnesses". Each engine has a different harness because of where the sending units are. And then there is the difference in ignition systems, fuel systems, etc. I guess I've lost track of what you are trying to do. Can you help me? If I read his first post he wants to add a factory tach to an 86 truck (5.0) that has lights not gauges. I wonder if he wanted to keep the lights and his harness if he could add a tach to his cluster and run the wires off the studs of the tach gauge to where they need to go for it to work? Not even use a tach cluster board as his cluster would not work because of the different number of pins. Dave ---- Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 26, 2020 Share Posted September 26, 2020 There are several "underhood harnesses". Each engine has a different harness because of where the sending units are. And then there is the difference in ignition systems, fuel systems, etc.I guess I've lost track of what you are trying to do. Can you help me?If I read his first post he wants to add a factory tach to an 86 truck (5.0) that has lights not gauges.I wonder if he wanted to keep the lights and his harness if he could add a tach to his cluster and run the wires off the studs of the tach gauge to where they need to go for it to work?Not even use a tach cluster board as his cluster would not work because of the different number of pins.Dave ----Dave - I'm pretty sure that an idiot light cluster has no place to put the tach. So in order to physically mount the tach he needs a gauge cluster. But, using your idea, he could use a tach cluster and hardwire the tach. But he would also have to re-pin the 14 wires from his current harness into an 18-pin connector. And since the 18-pin connector actually uses 16 pins, he would have to hardwire those two circuits. And he would have to make some other changes to go from idiot lights to gauges. The spreadsheet below maps the pins between the two connectors. As it shows he could hardwire the tach. But there are 4 other circuits he'll have to decide on. One pair is for the ammeter, and his underhood harness doesn't have a shunt so there's no way to run an ammeter. But he could go with a Rocketman volt meter in place of the ammeter and hardwire it. The other is the alternator warning light. That circuit is used to bootstrap the alternator so he will have to rig something to do that or the alternator won't work. But there are ways around that. Link to comment Share on other sites More sharing options...
Ford F834 Posted September 26, 2020 Share Posted September 26, 2020 If your goal is just to add a factory tachometer and get the factory gauges instead of warning lights, then seriously consider sourcing a tach cluster plus a cut off pig tail for the 18 pin plug. Then add wiring for the tach and gauges. The ammeter will be the tricky one as Gary already mentioned. Finding a complete “dash harness” in usable condition is a tall order. If you have not already examined one, note that the whole cab, plus the front lights, starting and charging circuits are all one big piece. The whole mess fills a Rubbermaid tub. If you do find a donor with a good wiring, my advice would be to pull EVERYTHING. Get every inch of wire and every connector that you can from bumper to bumper even if you don’t think you will need it. There are more year to year differences than you think and the the more complete your donor wiring is, the more options you will have for a clean install. I have encountered several changes in the connector plugs including the junction by the steering column that services the tank(s) transmission and rear lights, the plugs for the heater blower, the HVAC switch, the clock, and the stereo. No doubt there are others... a complete wire swap isn’t a bad plan, but it’s a big project and your main obstacle will be to find one. Link to comment Share on other sites More sharing options...
BARRYS83F100 Posted September 26, 2020 Author Share Posted September 26, 2020 There are several "underhood harnesses". Each engine has a different harness because of where the sending units are. And then there is the difference in ignition systems, fuel systems, etc. I guess I've lost track of what you are trying to do. Can you help me? If I read his first post he wants to add a factory tach to an 86 truck (5.0) that has lights not gauges. I wonder if he wanted to keep the lights and his harness if he could add a tach to his cluster and run the wires off the studs of the tach gauge to where they need to go for it to work? Not even use a tach cluster board as his cluster would not work because of the different number of pins. Dave ---- its for 1983 not 86 if it makes any difference and yes I have a factory style tach cluster. Link to comment Share on other sites More sharing options...
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