Some background info:
She's a 1992 Honda Accord DX Sedan, MT, no CC or ABS, with AC. 235k miles. All stock except upgraded head unit and speakers, which was done about 4 years ago and has never had an issue.
1 year ago, the door/trunk/brake light indicators started flickering on and off on occasion (all of them lit up and went out together, flickering erratically). One day, this became all of them lit up all the time.

I am fixing her up to sell, so I wanted to fix that annoying problem. I removed the cluster and inspected it's PCB. There was a large area that looked burnt and damaged right near where those indicators are. So I ordered a replacement cluster from a wrecker, as close to identical to mine as I could find (it came from a 1992 Accord with MT, but also had CC and ABS... not sure if that should matter or not for checking the fuel gauge's function?).
While waiting for the replacement, I put the original cluster back in. At some point later, I noticed the fuel gauge no longer worked. I didn't really do anything to the cluster when it was out... but I figured I must have caused this.
The new cluster arrived and it was guaranteed 100% working, so I hoped my problems were over. I immediately pulled the plastic cover off the back and it had a more-or-less identical area of burning/damage as mine did.
However, when I installed it, the door/trunk/brake sensors were all back to working properly, and the door chime now works, which I never even knew the car had. BUT STILL NO FUEL GAUGE.

I checked the sending unit in 3 ways... (1) Voltage checks at the 3-pin connection from the Honda service bulletin (it was getting 6V, returning about 3V, and ground was good), (2) removed it from tank and checked resistance with multimeter which varied from about 0 to 100 empty to full (3) ordered a new sending unit and plugged it in, moved float up and down and gauge did nothing. So I'm pretty confident it's not the sending unit!

I want to check the voltages at the cluster, but can't find the right schematic with those pin-outs.
The connectors and pins look fine, by the way. Definitely not a pushed pin or something simple. Besides, the voltage checks at the sending unit were good. I jumped the return signal line to ground (per the service bulletin) and the gauge did not start to rise, so the bulletin says the gauge should be replaced.

Maybe that cluster I bought that was guaranteed working actually had a bad fuel gauge and they didn't notice or check that?

So I guess I could also try a THIRD cluster, but it's been impossible to find the exact one for my car, and I'm not sure how much that matters. Can I use one from a 92-93 accord with an AT, or with CC, or with ABS? As long as it is the Nippon Seiki version, will any of that matter? Those are very easy to come by for about $50, so I could try that next?

If it were your car, what would you try next? Also, if you need clarification on anything else, please ask! Thanks!!!

 

I don't know the pin-outs for the gauge cluster, but here's what I would do (if I had a wiring diagram).

Just like you checked the fuel sending unit (0 to 100 ohms when you moved it empty to full). But you're checking that same signal at the wiring harness that plugs into the instrument cluster. What I don't see in your description is checking the wiring harness is intact all the way from the tank to the cluster. You mention wanting do do that and I agree.

I think you'll want a cluster from a manual transmission car. CC and ABS are just a couple lamps in the cluster without any purpose. I bet your original cluster probably had those sockets without any bulbs installed. But the automatic may have a different pulse-rate for the speedometer signal. I'm pretty sure the VSS for manual & auto are different from each other, and probably the final drive ratio is different.

 

​​​​​​Hi Jim,
Thanks for your insight.
​​​​​You have a good point about the speedo for the AT versus MT, but what do you think about the fuel guage circuitry on an AT cluster likely being identical? I would really only buy it to troubleshoot that guage failure. $40 is a cheap sanity check on the two clusters I have. I think they'll be the same in this regard. What do you think?

Also, on the harness, I did do the Honda service bulletin checks at the connection ahead of the sending unit. This wiring also powers the fuel pump. Ground was good, voltage to and from sending unit was appropriate with key turned on, fuel pump works fine.
Yes, as a redundant check, I would like to verify this again at the connector on the cluster. But I do think it would be redundant based on what I see in the back of the car. Wouldn't it?
I searched again for a better schematic but no link (the ones I found don't have the detailed connector pin outs).
I guess I'll just try an AT cluster that I can get locally for cheap.
Might at least be good for someone else to know if it works or not.

 

Have you tried looking on e-bay or books 4 cars for a factory service manual? I'm sure 1 or the other site might have one. Even if you sold it with the car, it'll help you out. I do think the clusters are basically the same, and the pin outs should be too. Have you verified the wiring between the gauge and the sending unit? Go from the pin out to the sending unit, and cycle the float to see if it's reading.

 

I suspect the cluster can be dismantled somewhat, but I never had to try that on my cars. That is, if you can't find another manual-trans cluster.

 

The only time I've had a cluster out, is to replace burned out light bulbs. But if you look in the FSM, they don't make the distinction between either gauge cluster, with only the AT getting a second plug in for the AT part (PRND4D3D2D1) lights.