AMC really started making changes in FSJs beginning in 1973. The electrical wiring and instrument cluster was one of the big changes. The instrument cluster had 3 round analog meter appearance which was very similar to those used in many AMC cars during the same period. The cluster looks pretty much the same from year to year from 73 through 85. The gauges were painted a little different for some models. The Emergency Drive and 4 Wheel Drive indicators are on the right side between the oil and amp gauges. The clusters don't appear to be electronically different through this period. Finding reliable technical diagrams for different model years is difficult. The speedometer options were 85, 100 and 120 MPH. What is posted here is from my experience with these type instrument clusters and is by no means the final word.

There are also some comparisons of the FSJ instrument clusters HERE.

Here is the cluster in Krista's 76 Wagoneer. It was
originally from a 74 model and is rated to 120 MPH.

Here is a sample of a 100 MPH cluster I found on Ebay in 2002.
It was NOS with 1 mile on it and did not include the surround
panel for the dash.

Back side of same instrument cluster.

We didn't buy this, but just copied the pictures for reference. Notice this one has a blue coating over the circuit board. A common failure for these clusters happens when the cluster is being removed from a vehicle and the wiring harness plug does not want to come off the cluster. The pins get broken or pulled away from the circuit board. Use some spray lubricant on the connections and remove the plugs gently if possible.

This 85 MPH instrument cluster was removed from an 81 Wagoneer
Limited with a NP219 transfer case. It still has the Emergency Drive lens
used for the BW1305 & 1339 Quadra Trac vehicles from 73 to 79.

Complete cluster

The wire map in the circuit board is the same, but not coated.
This view has the cluster installed in surround for the dash.

Notice on the lower-right side in the rear view of this cluster, there is a device plugged to two posts. The best I can tell from a couple different Chilton diagrams, this is called a Radio Noise Suppresser. These have a tendency to fail and cause outages in the instrument lights and some gauges. I tested a known good one with an analog volt-ohm meter and found that it is somewhere between 0.7 and 1.0 ohms. I had a known bad one on hand (open circuit) and pulled the shrink wrap and paper wrap from it to discover it is a wire wrapped device. From my electronic experience I would say this is some type of coil. The thought of it being a coil supports the idea that is is called a Radio Noise Suppresser. Why it was designed as part of the instrument cluster is beyond me. I noticed the wire is soldered to a steel rivet on each side. The rivets had some rust on them. Upon further investigation, I found the rivet was NOT making contact with the post contact on each side of the device. I de-soldered the wire and cleaned the connections with a finishing nail. Still no contact on one side. I decided to re-solder the wire to the rivet AND the post contact to insure proper electrical flow. This fixed it and it also now reads between 0.7 and 1.0 ohms again.

Here are some photos to sample the work done to repair the
Radio Noise Suppresser.

Re-soldered to posts

Installed on cluster