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Correct under dash harness for Tachometer

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BARRYS83F100

Correct under dash harness for Tachometer

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 ?

Gary Lewis

Re: Correct under dash harness for Tachometer

Administrator

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?

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

BARRYS83F100

Re: Correct under dash harness for Tachometer

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 ?

Gary Lewis

Re: Correct under dash harness for Tachometer

Administrator

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.

Gary, AKA "Gary fellow": Profile

BARRYS83F100

Re: Correct under dash harness for Tachometer

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.

Gary Lewis

Re: Correct under dash harness for Tachometer

Administrator

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?

Gary, AKA "Gary fellow": Profile

FuzzFace2

Re: Correct under dash harness for Tachometer

Gary Lewis wrote

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 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

Gary Lewis

Re: Correct under dash harness for Tachometer

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This post was updated on .

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.

Gary, AKA "Gary fellow": Profile

Ford F834

Re: Correct under dash harness for Tachometer

Administrator

In reply to this post by BARRYS83F100

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.

SHORT BED 4-DOOR DIESEL: 1986 F350 4x4 under construction-- 7.3 IDIT ZF5+GVOD

STRAIGHT SIX 4X4: 1981 F150 2wd to 4x4-- 300 I6 close ratio diesel T19, hydroboost brakes, Saginaw steering

BIG F: 1995 F-Superduty under construction— converting to 6.9L IDI diesel ZF5+DNE2

BARRYS83F100

Re: Correct under dash harness for Tachometer

In reply to this post by FuzzFace2

its for 1983 not 86 if it makes any difference and yes I have a factory style tach cluster.

Gary Lewis

Re: Correct under dash harness for Tachometer

Administrator

Barry - With two threads going on essentially the same topic you may get info that is seemingly at odds with each other. Given that, I'm going to post a link back to this thread in the other one so everyone knows they are connected.

But Jonathan/Ford F834 is 100% right. The harness you need is very long, headlight-to-headlight across around and through the dash, and there are lots of little wiring changes over the years. So you'd have to concentrate your search to probably 1982 to 1984 trucks. And even then I'm not sure it would be plug and play.

If I were doing it I'd almost for sure go with the approach Jonathan suggested of getting the 18 pin connector and a bit of wire with it, and grafting it into your system. Here's what I think the changes would be:

Pin Swaps: You'd have to pull the pins out of the 18 pin connector and your 14-pin connector, and put yours into the 18 pin connector in the positions shown in the spreadsheet

Ammeter: For this I'd have Rocketman change the ammeter in your new cluster to a volt meter. Plus you'd have some very minor wiring to do.

Alternator Warning Light: If you have a volt meter you don't need the warning light. So you could just put a resistor across the two wires, and that would bootstrap the alternator.

Oil Pressure Gauge: I think you have a switch instead of a sender, so you'd have to change that out on the engine. Not a big deal.

To my way of thinking that would be FAR easier than replacing the whole harness.

Gary, AKA "Gary fellow": Profile

Ford F834

Re: Correct under dash harness for Tachometer

Administrator

In reply to this post by BARRYS83F100

Barry, I have extracted the wiring from three different Bullnose trucks. It is a BIG job, and the ones I did were all fairly simple (IDI diesels and non-computer non-catalyst 5.8 HO). The only reasons I can think to justify a whole truck wire swap would be 1) your existing harness being so badly hacked and damaged that it isn’t worth repairing or 2) you want to add multiple options like factory cruise, interior lighting group, power door options etc., and can find a donor that has everything you want to add. I will say this again, finding a bullnose harness in good enough condition to use is becoming a very tall order. I would like to replace the poor condition harness in my 1981, but I have yet to find one that isn’t worse than what I have. I’ve been looking at four different junkyards for the past couple of years and no luck. I have a diesel harness, and may consider modifying it. My suspicion is even if you find a good harness, you may end up doing more work to it to adapt it than you would to just modify for the tach cluster.