speedometer and fuel gauge not working (moon gauge)

[DontPressureMe]

1988 chevy k2500 5.7 v8
as the title says, my speedometer and fuel gauge stopped working. ive already replaced the fuelpump, which came with the sending unit. whatelse could i look at?
i bought another cluster and swapped the parts around and put in the new cluster all together. it continues to not function. board looks perfectly fine and same w the guages.

 

[Russ B]

1988 chevy k2500 5.7 v8
as the title says, my speedometer and fuel gauge stopped working. ive already replaced the fuelpump, which came with the sending unit. whatelse could i look at?
i bought another cluster and swapped the parts around and put in the new cluster all together. it continues to not function. board looks perfectly fine and same w the guages.

I am in the same boat. My gas gauge does not work either (speedo okay). Like you I changed out the fuel pump module which did nothing. I pulled the cluster, which was tricky as you have to also pull the radio and heater controls to get to the right side screws of the cluster. The radio fought me, so when I reassembled I left the screws out of the right side. When I reinstalled the cluster I did see some minor movement on the gas gauge. However when I screwed down the trim that movement disappeared. The point here is I suspect there is a connection issue behind the cluster. I tried to clean the contacts but no luck. Right now I am thinking it could actually be my fuel gauge so looking for one. No close junkyards. Not sure how to test a gauge by itself, but working on that. I have the original fuel pump module so I could rig up the float circuit to that and use a battery. A point of interest. GM uses 0-90 ohm resistence for the float. I tested mine and it was screwed up so it could possibly have messed up the gauge. Anyway you are not alone in your pain!!!!

 

[ChRoNo16]

These gas gauges are known to fail. So much so that LMC truck sells just the moonie fuel gauge. replace your gauges.

 

[Russ B]

I am in the same boat. My gas gauge does not work either (speedo okay). Like you I changed out the fuel pump module which did nothing. I pulled the cluster, which was tricky as you have to also pull the radio and heater controls to get to the right side screws of the cluster. The radio fought me, so when I reassembled I left the screws out of the right side. When I reinstalled the cluster I did see some minor movement on the gas gauge. However when I screwed down the trim that movement disappeared. The point here is I suspect there is a connection issue behind the cluster. I tried to clean the contacts but no luck. Right now I am thinking it could actually be my fuel gauge so looking for one. No close junkyards. Not sure how to test a gauge by itself, but working on that. I have the original fuel pump module so I could rig up the float circuit to that and use a battery. A point of interest. GM uses 0-90 ohm resistence for the float. I tested mine and it was screwed up so it could possibly have messed up the gauge. Anyway you are not alone in your pain!!!!

Today I bit the bullet and did a continuity check from fuel pump all the way to the cluster. Have continuity. Pulled gage and tested points of contact on board. I have battery voltage on the top and grounds on other two points. So my conclusion is the fuel gage is shot. Now looking for that.

 

[Russ B]

These gas gauges are known to fail. So much so that LMC truck sells just the moonie fuel gauge. replace your gauges.

LMC no longer has that gauge, Rats......

 

[jus10inbrla]

This company has been good to me

MOTOR METER RACING W PRO 52mm 2-1/16" Fuel Level Gauge 0-90 Ohms with Warning Function Waterproof Black Dial White LED for Car Truck Marine Boat Yacht https://a.co/d/8rVC58n

 

[ChRoNo16]

LMC no longer has that gauge, Rats......

they are out of stock, just watch for them they will return