Gary Lewis Posted November 5, 2021 Share Posted November 5, 2021 I definitely have full gauges and no idiot lights. As for the tach itself, my plan is to physically remove it from the cluster I bought and install it in place of the tach delete plate in my current truck. I am 99% sure that’s what I did on my 84 back in high school and it worked. That said, it has been many years since I was in high school so…we’ll see how good my memory is. Well, this will be interesting. There were three flex circuits for 1980 and three for '81-86, as shown below: idiot lights; gauges w/o tach; gauges with tach. Shaun/Salans7 and I just had a discussion about this. He's not seen a vehicle w/o a tach have a flex circuit that supports a tach. In my case, I've added tachs to several trucks that didn't have them, and the flex circuits supported them. So it will be interesting to see what you find. Link to comment Share on other sites More sharing options...
Atlas75 Posted November 5, 2021 Author Share Posted November 5, 2021 Well, this will be interesting. There were three flex circuits for 1980 and three for '81-86, as shown below: idiot lights; gauges w/o tach; gauges with tach. Shaun/Salans7 and I just had a discussion about this. He's not seen a vehicle w/o a tach have a flex circuit that supports a tach. In my case, I've added tachs to several trucks that didn't have them, and the flex circuits supported them. So it will be interesting to see what you find. Well, maybe I swapped the tach and the printed circuit on my 84. Like I said, high school was 31 ish years ago for me. I’m guessing finding a green printed circuit that supports tach will be somewhere after unicorn on the difficulty list. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 5, 2021 Share Posted November 5, 2021 Well, maybe I swapped the tach and the printed circuit on my 84. Like I said, high school was 31 ish years ago for me. I’m guessing finding a green printed circuit that supports tach will be somewhere after unicorn on the difficulty list. You have the cluster with the circuit that obviously supports the tach. So use it. But you will want to read this: HOWTO: 81-86 gauge cluster in 80 model (gauge models ONLY!) Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 5, 2021 Share Posted November 5, 2021 You have the cluster with the circuit that obviously supports the tach. So use it. But you will want to read this: HOWTO: 81-86 gauge cluster in 80 model (gauge models ONLY!) And, having found that, I added this statement to our page at Documentation/Electrical/Gauges and then the Printed Circuit Pinout tab: These are the pin-outs for the printed circuit connections to the gauges. However, this is for 1981 - 86 trucks as pins 17 and 18 are swapped for the 1980 trucks. In fact, if you want to use a 1981-86 cluster in a 1980 truck you need to read this: HOWTO: 81-86 gauge cluster in 80 model (gauge models ONLY!) Link to comment Share on other sites More sharing options...
Atlas75 Posted November 6, 2021 Author Share Posted November 6, 2021 And, having found that, I added this statement to our page at Documentation/Electrical/Gauges and then the Printed Circuit Pinout tab: These are the pin-outs for the printed circuit connections to the gauges. However, this is for 1981 - 86 trucks as pins 17 and 18 are swapped for the 1980 trucks. In fact, if you want to use a 1981-86 cluster in a 1980 truck you need to read this: HOWTO: 81-86 gauge cluster in 80 model (gauge models ONLY!) As I was reading the article I came across this statement. You can install a factory tachometer into a cluster that was not designed for one, but that will not be covered here. Has this been documented anywhere? Link to comment Share on other sites More sharing options...
Atlas75 Posted November 6, 2021 Author Share Posted November 6, 2021 As I was reading the article I came across this statement. You can install a factory tachometer into a cluster that was not designed for one, but that will not be covered here. Has this been documented anywhere? I also just found this. Apparently someone is making them new?? Something about them looks off though. I’ll see if they have a website with more info. https://www.ebay.com/itm/1980-Ford-Truck-Printed-Circuit-Board-for-Trucks-W-Factory-Gauges-W-Tach-Box-78-/272131444371?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=711-127632-2357-0 Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 6, 2021 Share Posted November 6, 2021 I also just found this. Apparently someone is making them new?? Something about them looks off though. I’ll see if they have a website with more info. https://www.ebay.com/itm/1980-Ford-Truck-Printed-Circuit-Board-for-Trucks-W-Factory-Gauges-W-Tach-Box-78-/272131444371?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=711-127632-2357-0 Yes, LMC is carrying them. See this post. As for installing a factory tach into a cluster not designed for it, the gauge circuit w/o tach doesn't have the circuits for the tach. But the 4 screw holes are in the plastic of the cluster. And the connections are on the 4 studs of the tach that hold it in. So you can use ring-tongue connectors on the end of wires to provide power, circuit ground, ignition input, and a ground tell it that you have an 8 cylinder engine. Link to comment Share on other sites More sharing options...
Atlas75 Posted November 6, 2021 Author Share Posted November 6, 2021 Yes, LMC is carrying them. See this post. As for installing a factory tach into a cluster not designed for it, the gauge circuit w/o tach doesn't have the circuits for the tach. But the 4 screw holes are in the plastic of the cluster. And the connections are on the 4 studs of the tach that hold it in. So you can use ring-tongue connectors on the end of wires to provide power, circuit ground, ignition input, and a ground tell it that you have an 8 cylinder engine. Interesting. I wonder why the EVTM for 1980 only shows 2 wires to the tach? Link to comment Share on other sites More sharing options...
Atlas75 Posted November 6, 2021 Author Share Posted November 6, 2021 Interesting. I wonder why the EVTM for 1980 only shows 2 wires to the tach? I found a post from 81-F-150-Explorer on www.Ford-trucks.com from 2010 that says this: B post on tach goes to battery power I post (or C) goes to the tach test lead of the coil G is the main ground for the tach (this has to be grounded) 8 is only grounded on V8 engines I think I can get this wired up with that information. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 6, 2021 Share Posted November 6, 2021 I found a post from 81-F-150-Explorer on www.Ford-trucks.com from 2010 that says this: B post on tach goes to battery power I post (or C) goes to the tach test lead of the coil G is the main ground for the tach (this has to be grounded) 8 is only grounded on V8 engines I think I can get this wired up with that information. That info on the wire connections is correct. And I don't understand why the '80 EVTM shows only two. But the '80 EVTM is strange, so just add that as one more item to prove its strangeness. Link to comment Share on other sites More sharing options...
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