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Thanks to the help from Randy and Spook, I was able to pull the bezel out and remove the instrument cluster. Thanks guys. However, I was unable to find the problem. My car is a '93 945, NA, Regina system. Note, my circuit diagrams show the same instrument circuit for both the Regina and the Bosch systems.
Symptoms - Sometimes the fuel guage needle doesn't move when I start the car. Usually a whack on the dash just above the fuel guage will cause the guage to jump up to a normal reading. The temperature guage works fine.
What I've done so far - I cleaned all connections between the guage and the printed circuit. I even flowed solder onto the PC pad to give better contact as someone on the BB did. I took the cluster apart and cleaned and tightened the nuts holding the guage to its circuit board. I examined both the flexible PC and the guage PC for loose parts and cold solder joints. All look good and I'm a fair judge of solder joints. I also cleaned the contacts on the plug which connects the guage to the tank sender.
Next I connected the fuel guage meter, which was still out of the cluster, to a 12v power supply and connected a 60 ohm resistor to simulate the sender at about 1/3 tank full. The guage read fine and never refused to move.
I put everything back together in the cluster and reinstalled the cluster. The problem remains. Sometimes the needle won't move and a whack on the dash gets it going.
My guess - I was wondering if the 12v from th eignition switch had an intermittant but if it did, all the guages would act up and they are working fine. That leaves me with the idea that there is an internal loose connection in the meter movement. Of course there is no way to see that. The connections to the stator winding of the meter seem solid. The other possibility is that the 12v supply from connector D pin 4 to the meter has a loose connection.
Has anyone on the BB seen this problem and found a fix?
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