BAC Forum

General Boards => Technical Support => Topic started by: Mack Turner on December 07, 2020, 12:38:28 AM

Title: Gas gauge points at 4:00 and doesn't move.
Post by: Mack Turner on December 07, 2020, 12:38:28 AM

My gas gauge was working fine earlier today and then I noticed it was pointing at somewhere around 4:00 and hasn't moved since, does anyone know what I should measure on the back is it a variable voltage that will change depending on how much gas is in the tank?

Title: Re: Gas gauge points at 4:00 and doesn't move.
Post by: Carl Boger on December 07, 2020, 01:18:01 AM

You should be able to ground it out on the back of the gauge and get the gauge to move one way or the other.  It is likely a faulty gauge or sending unit.  Less likely is the wiring between the two.  I had to replace the sending unit on my coach to get the gauge to work.  It wasn't to hard to get to, but the tank has to be under 1/2 full since the sending unit is on the drivers side of the tank about 1/2 way up.   

I have attached pictures of my sending unit.  It is fairly generic, but I ordered one of the original types because I didn't want to take the old one out while looking for another leaving a hole in the side of the tank.  I believe it is the same as yours.

If it turns out you need a new sending unit be sure it includes the gasket.

Title: Re: Gas gauge points at 4:00 and doesn't move.
Post by: Eric Maclean Co-Admin on December 07, 2020, 01:55:40 AM

Mark
The connections at the sending unit in the tank of your coach are  spade terminals and because the unit is mounted beside the left front wheel just below the frame rails these connection's get corroded causing the bands to loose it's signal.
Simply cleaning the connection usually cures the problem.
If not just connections then in the coach assist section there is a troubleshooting guide for the gauge and sending unit.
Under the  Beaver manuals 1974 to 1996 section Safari 1994 - 2001( misc. Diagrams and fixes)
Hope this helps
Eric

Title: Re: Gas gauge points at 4:00 and doesn't move.
Post by: Fred Brooks on December 07, 2020, 01:20:35 PM

    Mack,
  I am pretty sure it is a "90 ohm" sending unit for your fuel gauge. As the arm on the sending unit moves up or down depending on the fuel level, it changes the resistance (ohms) going to fuel gauge. Example: full tank is almost "no ohms" so the gauge reads "full". An empty tank, the sending unit is at "90 ohms resistance" thus making the gauge read empty.
  As Eric stated: clean the connection at the spade connector first before driving or emptying the tank below the sending unit location. Hope this helps, Fred

Title: Re: Gas gauge points at 4:00 and doesn't move.
Post by: Mack Turner on December 07, 2020, 07:18:22 PM

Thank you everyone for your help, turns out it was a loose spade terminal on the back of the gauge as soon as I moved it, it started working again.

Title: Re: Gas gauge points at 4:00 and doesn't move.
Post by: Eric Maclean Co-Admin on December 07, 2020, 08:35:25 PM

Mack
Most of the time it's the simple things that cause these problems and the best part is all it costs is time to fix them.
Eric