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Yesterday I responded to the fella a few posts down concerning his INOP fuel gauge on a 940 that sometimes responds to a whack on the dash board.
Last night my wife reminded me of her flakey gauge which has seen numerous attempted repairs over the past year, including the total replacement of the gauge itself. It slowly got to the point of not responding even to vigorous whackage upon the dash board.
My friend who is a Master Volvo Tech told me that usually the comb connector in the back needs to be re-crimped. After I did that 3 times he told me that if the re-crimp doesn't fix it, then it is in the electrical interface between the 3 screws that hold the gauge in place, with the flexible PCB sandwiched in between.
My buddy tells me the ONLY way to fix this for good is to lay a small amount of solder, very quickly and VERY carefully to the contact points under each screw.
This sounded WAY too dangerous for me to try. One false move and I could make a burn through or destroy the whole cluster. So I tried everything else first. I re-formed the flex pcb. I brushed on contact enhancer, I sanded, I tightened. Each time the repair would last for a minute, if that.
HERE IS THE PROBLEM.....
**>> ONCE AGAIN <<** Volvo has gone the STUPID ENVIRO-GREEN-WEENIE route with their design.
#1 The flex pcb, while very environmentally friendly to manufacture, easily deforms and becomes brittle with time. Ask ANYONE who has a 240 with tail light problems about these little beauties...
#2 The retainer/conductor screws are supposed to be cadnium plated. But cadnium is bad-bad for the environment. So the 3 little screws are coated with some other shit that blooms into galvanic corrosion after a while even though they 'look' ok.
The fix is in. The screws must be soldered.
Use a light iron with temp control. Try to hold ~700 degrees f. Use a normal 60/40 rosin core solder. Be very careful not to melt the plastic substrate as you heat up. I like to keep a can of electronic freeze spray to douse the hot spots immediately after flowing a bead of solder. In a pinch, a can of 'compressed air' turned upside down will achieve the same thing.
Solder all 3 screws to the pcb traces and you are done.
No more fuel gauge problems.
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