fuel guage or?

[GJORGENSEN]

I just was at a friends house and he has a 71 long bed 3/4 ton The problem he is having is that his fuel guage will only read up to 1/4 tank when full. I tried another sending unit that he had that tested the same as far as ohm reading goes. (I am an electronics tech). It reads from 12 ohms when down to about 105 ohms when lifted up. Don't know what they are supposed to read though. If I take the wire off the unit the guage goes to full. This all happened when he backed into another truck and had a good jarring. It hasn't read right sice. Don't know what the problem is or where to go next. Anyone have the same experience to help? Wednesday I am going there and pull the dash panel out and check another problem that is crazy which is when the windshield wipers are turned on high tthe washer pump starts to run also. HELP!!!!!!

[Sams_71]

Hi,

Don't know about what effects that the accident would have on the gauge or the wipers. But, my gauge used to do the same thing, read 1/4 when full, I swapped it for one from a salvage yard and this one works fine. Come to think of it though, I was told that a tree did fall on the bed of my truck when the original owner had it.

Sam

[GJORGENSEN]

I double checked his sending unit and even took mine out and tried it but got the same results. Indication of 1/4 tank. It has to be in the fuel guage or maybe the resistor on the back of the guage. Anyone ever take a reading on this resistor? This one reads 64 ohms. Don't know anything else it could be on the guage.