I changed my from a "Standard Dash Cluster" to a "GT Style" on my "72 Ranchero. I had no problem getting everything to work correctly with the exception of the "Amp meter". I have wiring diagrams, but for some reason can not get the meter to work, I even changed out meters thinking that could be the problem (it wasn't). Somewhere along the line I am not wiring it in correctly. Any help would be greatly appreciated! Thanks, Dan
The older fords I am familiar with all use an external shunt type ammeter. Located in the power wiring between the hot side of the starter solenoid and the chassis wiring (pretty much everything except the starter) is a specified length of a specified gauge wire. The two ammeter leads attach to the two ends of that wire. It works by measuring the voltage drop across that external wire (actually, the difference in potential across that wire induces a tiny current in the ammeter).
Thanks for the replies! Now having the correct instructions for the required "Shunt" clears up why I could not get it working. I am assuming the "Insulator Junction Block" can be any insulated terminal block, correct? One other question, the "Yellow Wire" shown coming off the "Insulator Junction Block" marked ~~~ is going to be attached where or to what? As always your help is greatly appreciated! Dan
That is the original wiring, and that wire goes to big connector at the firewall that connects to the fuse block. The junction block is as found here: https://www.nationalpartsdepot.com/store/?p=catalog&mode=newsearch&search_str=14448&parent=1&year=0
Hi everyone, I bought my self a 1979 Ranchero about three years ago. I am having a problem finding a place to purchase the junction block that hooks in between the solenoid and the ammeter. The link that 72GTVA has provided takes me to the home page of National Parts Depot and not to the exact part that I need. I do understand that the link that 72GTVA has provided is six years old. I was wondering if there is any other place I could purchase the part that I need. Thank you in advance. Peter
It never came with a junction block, so most of the positive wiring was hooked up to the solenoid, which many people told me it looked like a fire hazard. Thank you again for responding to my message and for the new link that you have provided. Peter
Oh, so you don't have a factory ammeter? OK, well, if you need photos of a factory install, let me know, and I can set you up with them.
Babe has a shunt; it's necessary to keep from catching your rig on fire. I'll go ahead and shoot the pics, post them up here. I may even have pics on my computer already.
Hi everyone, Could you post a picture of the original factory installation of the junction block ? I dont get any ammeter working, neither the original one, nor an after market part. I have the junction block and shunt wires installed, checked it over and over. Its getting very frustrating. The only guess I have is that I still have too many wires on the solenoid, that should rather go to the junction block.... Please see picture of my installation.
This is partly my fault; I have a bad tendency to forget to do something simple, so my apologies. I will try to either find the photo, or shoot a new one to post.
Hello, due the frustrating situation, I seekd for help from so called "experts",i.e. "specialists" that should be experts regarding car electrics. I provided them the original wiring drawings, cleaned all cables, opened the sealed wiring harness ( so that they can see which cable goes where) and explained the problem in simple , easy understandable words. Four workshops did not understand the problem, confronted me with complicated theories or denied to work on an oldtimer, so, no help from this side. The only idea I had was to try to look into the shunt. As I did not trust the original shunt, I created a primitive shunt, to see what happens. My shunt was placed between the battery and the main positive lead - I included the wire to the starter motor as well, as this sucks the largest amperage. This setup showed some part success. Starting the engine caused the Ammeter to go halfway into the minus ! However, switching on headlights - even high beam- did not show anything on the ammeter ! My guess is, that my shunt does not create enough resistance ( 10AWG wire, about one meter long ) . What do you recommend ? Would it be a good idea to enlarge the length of the 10AWG wire to, lets say 3 meters ? If I did this, I would of course take the starter lead out of this circle, as it would presumably burn the shunt...
On my amp meters I did minor surgery to free up the pivot points that hold the needle in place. They were built too tight to let the needle move freely. At best those Ford amp meters are just a hint at what is happening but after freeing up the needle movement they would register a draw as small as the brake lights turning on.
Hi, thanks for the information. I have done this at the beginning to be sure it works propperly. It moves freely, even when I blow against the pointer. It is not the ammeter, its the wiring. Any pictures of your wiring would be helpful. The shunt is the key. In my current setup, I have for example no positive readings on the ammeter. I am sure, the alternator needs to be in the shunt as well.Can remember , when I got the car, the alternator was on the shunt, but forgot where it was connected. The workshop that worked on the car made a lot of changes and I need to get the electrical system back to the original setup, to make the ammeter work again. So, I hope that some others read this and can help me with pictures where I can see wich cable goes where Thank you for your help ! Ilja
