My fuel gauge on my 83 CJ7 doesn't work. I have checked the ground and it seems like it has a good connection. The temp. gauge next to it is also not working. Any ideas on how to test the gauge itself to see if it still works from under the dash? I have a Resistance gauge to tell if the circuit is working to the back but I am having problems figuring that out today.
I am not 100% on all of this but I will tell you what I know. If both of these gauges are not working there is probably a power problem. The temp gauge receives it's power from the fuel guage so if they are both not working check the power(I post)at the fuel guage. If you do have power I would guess that it is either the guages or the senders(unlikely for both to be bad. Good Luck and I hope it helps.
I had the same problem on my 84 CJ-7. However I opted to change out the gauges. I cut new holes in the dash and put regular gauges in. When I did this everything worked. I also tried switching speedo assemblies before this just to find that the gauges were bad in it too.
Also I was reading up in 4 wheel drive's catalog and they recommend changing both the fuel and temp gauges as a pair. This of couse in your case will be nessecary. these gauges aren't very expensive adn can be picked up from 4 Wheel Drive Hardware. Hope this helps.
'84 CJ-7 Junkyard TBI 360/T18/D300, 4" 4WDH Lift, D44 front with ARB and HS/D44 Rear w/ Detroit, 4.56s, 36" Iroks, TFI, TJ flares, Homemade rocker guards and bumpers with swing out, Optima Yellow Top, M8000, York OBA, 6pt cage
"when you're up to your *** in alligators, it is hard to remember that your original intention is to drain the swamp"
Find the wire going to the sending unit off the back of the gauge. ground a test light and touch the end to the stud. The light should blink and the gauge should go up. If the light doesnt blink then check the power wire going into the gauge.If it doean't light then there isnt any power going to the cluster.If it does light on the power side but doesn't blink on the sender side then the voltage regulator is bad.if it blinks and the gauge goes up then the problem is in the wiring from the gauge to the sending unit or the sending unit itself.
I'm still messing wtih the gauge. I can't find the fuse for the gauges but I assumed if I was getting current from the red wire then the fuse was ok. I measured it and it read about 12 Volts. I'm thinking the gauges have gone bad. Seems weird that both have gone bad.
I'm working from memory here but if I recolect right there should be a power wire to the fuel gauge input stud. there should be a wire from a 2nd stud to the sending unit.There should be a stud in the middle with a flat strap connecting it to the temp. gauge. A wire goes from the temp gauge to the sending unit. If you have power to the fuel gauge but no power out then the voltage regulator is bad and you will have to replace the fuel gauge. If you have power on the sending unit side(blinking test light) then the problem is between the gauge and (including) the sending unit.