84-460-Project Posted October 13, 2019 Share Posted October 13, 2019 I have my instrument panel out, battery connected and no key in the ignition. Just for kicks I broke out the test light and started checking each circuit on the main connector for the instrument panel. Circuit 8 (654) Yellow/Green and 9 (655) Red and Orange are hot (in this case - always hot). Looking at the 1986 EVTM pg 15 these circuits feed the ammeter on the instrument cluster. I've never seen this working (one of the reasons I have the cluster out). Are these circuits always hot, or do I have an issue with one of my connections? Thanks Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 13, 2019 Share Posted October 13, 2019 Yes, those circuits are always hot. As you can see in the schematic below, which is from the '85 EVTM but should be the same as the '86 one, the red/orange connects to the always-hot side of the starter relay, which is also where the shunt connects. And the yellow/green connects to the other end of the shunt, and that's always hot as well. So the ammeter is watching the current flow across the shunt. If it flows from the battery to the right, meaning towards the truck, then it shows a discharge. But if is flows from the alternator toward the battery, meaning the the left, then it shows a charge. A test for the ammeter is to turn the headlights on w/o starting the truck. The ammeter should show a discharge. Link to comment Share on other sites More sharing options...
84-460-Project Posted October 13, 2019 Author Share Posted October 13, 2019 Yes, those circuits are always hot. As you can see in the schematic below, which is from the '85 EVTM but should be the same as the '86 one, the red/orange connects to the always-hot side of the starter relay, which is also where the shunt connects. And the yellow/green connects to the other end of the shunt, and that's always hot as well. So the ammeter is watching the current flow across the shunt. If it flows from the battery to the right, meaning towards the truck, then it shows a discharge. But if is flows from the alternator toward the battery, meaning the the left, then it shows a charge. A test for the ammeter is to turn the headlights on w/o starting the truck. The ammeter should show a discharge. Gary, thanks so much. This site is an outstanding resource and is consistently proving its value. I freakedout out a little when I went to reinstall the instrument cluster and one of the "hot" circuits made contact and a little smoke came out. Hopefully it didn't do to much damage. Lesson learned - disconnect the neg terminal when reinstalling the instrument panel. Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 14, 2019 Share Posted October 14, 2019 Gary, thanks so much. This site is an outstanding resource and is consistently proving its value. I freakedout out a little when I went to reinstall the instrument cluster and one of the "hot" circuits made contact and a little smoke came out. Hopefully it didn't do to much damage. Lesson learned - disconnect the neg terminal when reinstalling the instrument panel. Glad the site is helping. Sure hope you didn't let too much smoke out of your wiring. Link to comment Share on other sites More sharing options...
Steve83 Posted October 14, 2019 Share Posted October 14, 2019 ...the ammeter on the instrument cluster. I've never seen this working (one of the reasons I have the cluster out).They never worked - even new. That's one reason Ford (& every other automaker) switched to a voltmeter. It's relatively easy to swap one in, and it will be much more-useful to you. This shows my heavily-modified cluster, but focus on the voltmeter in it & the NEXT pic: https://supermotors.net/getfile/76023/thumbnail/cluster-front.jpg Link to comment Share on other sites More sharing options...
Rembrant Posted October 14, 2019 Share Posted October 14, 2019 That's one reason Ford (& every other automaker) switched to a voltmeter. It's relatively easy to swap one in, and it will be much more-useful... Steve, What Voltmeter did you swap in there? One from a Bricknose? Do you have a write-up on that somewhere? Link to comment Share on other sites More sharing options...
Steve83 Posted October 15, 2019 Share Posted October 15, 2019 What Voltmeter did you swap in there? One from a Bricknose?Possibly, but more likely '92-96. The guts of the meter are probably the same - only the face might be slightly different.Do you have a write-up on that somewhere?Not on that exact cluster, but the concept & process is very similar to what's shown in this, the NEXT several pics, and the links in the captions: https://supermotors.net/getfile/900909/thumbnail/voltmeter01.jpg Only the '80-86 ammeter is easier because it's not full-current, so you don't have to worry with the big ammeter wire - just abandon the 2 small ones (because they're always-hot, and you don't need the voltmeter on all the time), and add a jumper from the switched-hot on the cluster to the new meter, and another from the new meter to cluster return (ground). You'll probably use the original ammeter face, and just learn where the voltmeter needle sits (because it would be difficult & expensive to 3D-print a new plastic face with volt markings). Link to comment Share on other sites More sharing options...
kramttocs Posted October 15, 2019 Share Posted October 15, 2019 That's one reason Ford (& every other automaker) switched to a voltmeter. It's relatively easy to swap one in, and it will be much more-useful... Steve, What Voltmeter did you swap in there? One from a Bricknose? Do you have a write-up on that somewhere? The gentleman at Rocketmans is great to work with. I had him convert mine. https://www.ford-trucks.com/forums/1339746-how-to-swap-amp-meter-to-volt-meter.html Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 15, 2019 Share Posted October 15, 2019 The gentleman at Rocketmans is great to work with. I had him convert mine. https://www.ford-trucks.com/forums/1339746-how-to-swap-amp-meter-to-volt-meter.html Yes, he is. He did mine as well. And since I'll use that on Big Blue I'll have to have him do another for Dad's truck. Link to comment Share on other sites More sharing options...
grumpin Posted October 16, 2019 Share Posted October 16, 2019 The gentleman at Rocketmans is great to work with. I had him convert mine. https://www.ford-trucks.com/forums/1339746-how-to-swap-amp-meter-to-volt-meter.html Yes, he is. He did mine as well. And since I'll use that on Big Blue I'll have to have him do another for Dad's truck. Thought I’d show y’all the high falutin’ gauge I installed! Link to comment Share on other sites More sharing options...
Recommended Posts