Jump to content

Fuel gauge


Recommended Posts

Need to determine if fuel sending unit is functioning properly. Disconnect connector either at fuel pump (C139) or the flat six pin connector (C157) near parking brake. Using this specification, 0Ω's=Empty and 88Ω's=Full. Connect DVOM to C157_C (fuel pump side) and ground or connect DVOM to C139_A and C139_B (fuel pump side). Measure resistance. Example for good fuel sender would be, if you think you have a half tank of fuel, measurement should be around (non linear) 44Ω's.

Link to comment
Share on other sites

Yeah, that will determine which cluster pins will need to be tested for power and ground, but since fuel gauge is your only problem and all other cluster items work, suspect printed circuit or faulty fuel gauge or possible faulty Low Fuel Warning Module, if equipped.

Link to comment
Share on other sites

Fuel gauge has three legs. Power, ground, and the fuel sending unit. Sending unit leg seem good from your point of measurement to sending unit. Check power (key on) and ground (key off) at disconnected Instrument Cluster C203. Re--measure fuel sending unit.

C203_18 (B+).

C203_10 (GND).

C203_17 (fuel sending unit Ω).

 

Using the following link for reference:  http://www.bteventures.com//mj1988electricalmanual.pdf

Page 29, Page 78, Page 95

Link to comment
Share on other sites

13 minutes ago, 89jeep-comanche said:

#18 has power with key on

#10 has 0.1 ohms with key off

#17 has same ohms had when I tested C139

 

Wiring tested good.

 

On 11/30/2018 at 7:26 AM, 89jeep-comanche said:

I moved the needle  y accident when I was wiping dust out. Does that hurt anything internally on the gauge? Or effect readings?

 

Don't know of any test for the LFWM. Seems to be either fuel gauge or printed circuit. Look for open circuits on the printed circuit. Maybe it was a bad day to dust.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...