Well I guess it's take apart the gauge cluster time. No luck getting any life out of the gauge when putting the 68 ohm resister across the pins in the left rear well where that plug is very easy to get to. I pulled the connector on the back of the cluster to double check that I had the right wires and I got exactly 68 ohms there so all is good with the circuit and the sender. That's the good news. Anything I should be careful NOT TO DO as I disassemble the cluster besides don't pull to hard on anything and don't forget to take pictures? TD

 

before replacing it, you might reflow the solder joints, they can all look good and still be funky... TurboBricks | High Performance Volvo Club

I need to do this to the speedometer on my 92, I've already replaced all the caps but it won't read above 42MPH most of the time.

 

I have the cluster out on the bench again. I checked out that TurboBricks link but I can't detect the solder joint defects in his pictures so I don't know what I'm looking for. Reflowing solder joints sounds like a way I might destroy my whole cluster? Can the fuel gauge be taken out of the cluster & tested by itself? TD

 

if you've had some practice doing electronic soldering on circuit boards, its easy to do, if you haven't, well, find someone who has? Is there an old school been-there-forever TV/VCR/etc repair place in your town?

 

I'm researching this reflow idea with a friend who has a steadier hand than me. Are you referring to just the three screw points where the fuel gauge connects to the printed circuit board, or doing the whole cluster in an oven as that video link showed?

In attempting to open up the cluster, should I need to replace the gauge, I have reached an impasse. I've removed all the logical screws but something is still keeping the assembly from separating. Is there a hidden screw somewhere? TD

 

my speedometer needs reflowing. I'd resolder the whole cluster, using some quality electronics solder like Kester #66/44 rosin core, the old lead-tin stuff, not the crappy new silver stuff, and a temperature controlled soldering iron with a medium circuit board tip, I might even use a 'solder sucker' to remove most of the original solder of each joint then flow it with fresh. key trick to soldering is, the solder always flows towards the heat... so you heat one side and apply the solder to the other side.

I've been soldering electronics stuff since 5th grade circa 1965 so it seems easy to me.

 

I'm zeroing in on the culprit. I've gotten an actual cause effect reaction. Two of the three screw locations where the gauge connects are directly feed by the appropriate leads on that long plug connector, #3 and #4. The third one whose trace runs up under that metal box above it seems to be the culprit. When I reassembled it all, connected all the leads, turned on the key, nothing was different. I then began gently tapping on things and when I tapped on that third screw, the gauge sprang to life. I replicated that event several times with the gauge being lifeless each time I turned the key off & then back on and then it would react to tapping that screw. I took the metal box off and that trace just passes under it so I'm guessing the break is in the gauge itself. Any hypothesizes or suggestions on how to trace it from here? That gauge seems like a very complex bit of circuitry, a far cry from the lever in the glovebox of my VW you'd flip when the car started to sputter!! TD