Volvo: 91 volvo 740 speedometer/ fuel gauge not working, fuel gauge, volvo 740

Question
ok so i checked the fuel gauge for power at the fuel pump and both sides were grounded and i just wasnt sure if it only powered up when the fuel got low because when i put power to the wire the gauge dropped and the low fuel indicater came on. my question is this:  is it possible that my float is stuck or do i have a power problem? next my speedometer/odometer doesnt work and hasnt since i bought the car. question:  where is the best/easiest place to start looking for the problem?


Answer
Dave,
Yes the float (sending unit) could be stuck. If you have the sending unit out you can turn the float unside down, turn on the key and see it reads full. Now let the float go down half way and see where it reads. If nothing shows:


Remove battery negative lead.
Unplug connector and measure between the white-gray and brown leads with an ohmmeter. Resistance should be between 0 and 280 ohm with a 60-liter tank (15.9 US gal.) .
It should be between 0 and 367.5 ohm with an 80-liter tank (21.1 US gal.) .
For 1993- models, it should be between 130 and 2 ohm with a 60/80-liter tank (15.9/21.1) .
For any other resistance, the sensor should be changed.

The speedo works off a sender in the rear axle make sure the wires are not broken. If wires are ok, test for power at the rear of the speedo cluster to the speedo. That is the green/white wire center of cluster in a three connector plug. You will be looking for a AC signal with the rear wheels spinning and it will increase as the speed rises. If you have power then looks like you need to teat the circurt card at the cluster and the speedo itself.