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Volvo Tech Bill
Volvo Tech Bill, ASE Certified Technician
Category: Volvo
Satisfied Customers: 103
Experience:  12 Year Volvo Technician/Expert Rated/Shop Foreman @ Best Volvo of Rochester, NY. ASE 1-8 + L1
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Where is the fuse for the fuel gauge in a Volvo 740?

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I have a 1992 Volvo 740 wagon, non-turbo, the electrical schematic says there is a fuse in the line that goes from the gas gauge to the gas tank, where is that fuse located?

Hello, and Thank You for using JustAnswer.

The fuse you are looking for is actually mounted on the combined instrument assembly, top/back side. I personally have never looked for it before now, but the wiring diagram shows it there. The problem is that it feeds all of the gauges and lights in the cluster. If the fuel gauge is the only one affected, I would target an actual sending unit fault, rather than the instrument cluster. It's not uncommon for cars of that age to have corroded wiring going into the sending unit. This would require replacing the sending unit (level sensor). The harness connector for the pump/sensor is located behind the left cargo/trunk panel. You should be able to separate the connector, and check resistance through the sensor. If it's open, fault found. The diagram shows a brown wire, and a black/white wire leading to the sensor. If this doesn't help, let me know of any other specific faults and/or diagnostics already done.

Volvo Tech Bill and 4 other Volvo Specialists are ready to help you
Customer: replied 8 years ago.

Sorry for the delay getting back to you, I've been gone most of the day! I had a mechanic friend of mine check to see if there was any current going to the fuel tank and he couldn't get one, he said if the wire had some current in it to the gas tank the gauge would register as soon as he probed it, so his conclusion was that it could be the fuse, but even he did not know where it was even though his schematic showed one! Where on the back of the cluster is it located? I replaced the cluster because I was told it was the problem, so I have the old cluster in front of me, but I can't find a fuse, all I find are the bulb sockets for the cluster!

The fuse is shown on the back of the cluster, top, left area (with the back side towards you). Again, if other gauges work (clock excluded), and warning lights come on when the ignition is turned on, the fuse is fine. It feeds all of them. A resistance check of the sending unit is needed. Isolate the unit, like I said before, disconnecting it in the cargo area. Check the resistance through the unit (ck above for wire colors). The voltage and current through the sending unit is very minimal. Honestly, I'm not sure what kind of voltages one would see; it's never come up, so to speak. If you really want to be sure, jump a 100 ohm resistor across the harness terminals leading to the sending unit, and see what happens at the gauge.

Let me know how you make out.

Customer: replied 8 years ago.

Bill,
Thanks, I'll show your answer to him! I have a new fuel sending unit! What does the fuse look like on the left side of the cluster, because all I see is bulb sockets and what looks like male plug in sockets? Everything else on the cluster works fine except for the gas gauge!

Gary,

I personally have never looked for this fuse, so I'm not sure what it would look like. It is shown on the upper left area of the circuit board with the board facing you. The problem, like I said though, is that fuse feeds all gauges and lighting in the cluster. If the sending unit is indeed new, working OK, I would next check resistance through the sending unit right from the cluster harness. This value should match within a few ohms of a reading taken right at the sending unit. If wiring to and from the sender are OK, then the gauge itself, or a circuit board on the cluster are at fault. Try looking closely at the board on the cluster for loose solder connections. These can be tricky to find. A magnifying glass would help with this.

Let me know how you make out, Bill

Customer: replied 8 years ago.
Bill,
Thanks for the tips, my friend should be able to figure it out from what you've written, I will let you know what happens! I was thinking the fuse was in the line from the gauge to the tank! I still can't find it on the back of the cluster unless it is hidden under the circut board, is that possible? it seems reasonable that it would be close too, if not on the cluster, but I sure can't find it! The gas gauge is on the right of my cluster when looking at the back! What a fiasco this has been, who would have thought a simple thing like a gas gauge malfunction would be so hard to track down!
Thanks again.
Gary

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