Roadrunner fuel gauge not working

LOL OK... Would still want to see that damn needle move though... I got a lot of time in money trying to see that needle move LOL

wire 2 AA batteries in series. So they equal 3 volts
put a wire from each side of the batteries to each terminal on the gauge.
It should move to half.

so would i put both AA' batterys next to each other and then one wire from the + sides and another wire from the negative sides?

Ok i just did it on my old dash, and the gauge went to 3/4 . What would make the gauge not work in the car if my sender wire is good all the way to the plug? I do not have my AMP gauge hooked up if that matters at all

with a tough one like this you might simplify it & take off the voltage limiter & with some jumpers run 12V to the limiter then from there to the input side of the gas gauge terminal in the pic (pull the round electrical connector off of the back of the printed circuit to isolate it) then from the other gas gauge terminal all the way back to the tank & see what you get.(ground the VL case too)

even if the wire is good from the sending unit, it could be either the circuit board, or the plug to the board.
ground to the dash.

I just took a test light and there is power on 2 of the spade connectors that the voltage reg plugs into. The plug has a good connection as i got a visual on it.

I do still have the autometer fuel gauge hooked up in line as well,not sure if that would affect it. I went to the sender and grounded the sender wire out from the rear of the car and the autometer gauge went full,but the dash gauge did not move.

If the cluster wasnt grounded good enough(which i doubt) where would you reccomend running an additional ground strap from? Do i put it on one of the studs from the back of the gauge?

see if you get power to the gauge.
Just incase it is the board.

Then trace down where it is grounded. The screws make contact. And ground it there.

sorry, im not great with electrical.
how would i see if the gauge is getting power?

my dash lights work.... so i think my cluster is grounded but i will add an additional.

The plus side you attached the battery to, put the test light there and see if it lights up.
You may just not be getting the feed to the gauge.

ok i have flashing power on the stud closest to the amp gauge.

The gas gauge itself is good. Grounding the lead at the gas tank sending unit makes the autometer gas gauge swing over to full, correct? You might jump directly from the tank sending unitforward to the gas gauge downstream terminal (one of the 2 on the pic) & w key on see what you get.

i'm no electrical guru but i think you should disconnect the autometer gauge for your testing. my gas gauge doesn't work either so i run an autometer, and while i was playing around trying to get the factory gauge to work, if i remember correct having both gauges hooked up caused problems. again, just a thought, i could be wrong. good luck

I may be mistaken but you said the amp gauge is not hooked up(they usually burn up, been there done that). I'm pretty sure the power through the amp gauge feeds power to the whole cluster. Somebody else might need to chime in but I think this is the case. Hope I helped.

Ok spent a few more hours under the dash, still nouthing.

I hooked up my amp gauge- no change

I disconnected my autometer fuel gauge.

I took the sender wire i had ran to my autometer gauge, and put in directly to the NON flashing power stud on the gauge itself. no change.

My dash (backlights) do not work,or sometimes just a few work. There is NO power to the (instrument fuse ) on my fuse block ,it uses orange and tan wires. I put powere to it ,but that didnt give me anything either.

I tried running additional ground wire from the cluster to a good ground, with no change.

My dash dimmer wheel only turns on my dome light, it does not dim the dash lights (which i do not have).

Not sure where to go with this... The back of the gauge has a Flashing power ,so it must be getting power..

Not giving up yet,just stumped....

Does your temp gauge work correctly? If so, the VR is OK. Look at the picture. Note the 3 slots where your voltage limiter plugs into. The center (with the extra lead from the capacitor) must have steady 12 volts referenced to ground. The terminal to the right is pulsed 12 volts which averages to 5 VDC, so a test light will flash from that point to ground. the terminal to the left of center is ground. See the threaded stud directly below the center VR terminal. That is the side of the fuel gauge that goes to the tank sender. With the ignition key "off" measure resistance from that stud to ground. You must have from 10 to 75 ohms depending on tank level(10=full). Next, plug in voltage regulator, turn ignition key to on and use test light on stud to ground. You should see a flashing test light, or varying voltage with a multimeter. If you got that, its gotta work!

Forgot to add:

1. Gauge resistance between the 2 threaded studs ~12.5 ohms.

2. Check those two fuel gauge nuts for tightness and corrosion. Mine were loose and caused a low tank reading.

The dash can be bench tested with a 12 volt power supply and a 100 ohm, 2 watt potentiometer, or some 5-10 watt resistors in the 10 to 50 ohm range.

thanks for replying!
i dont have the temp gauge hooked up.
the center slot has steady 12v when ign is on
The slot to the right has NO power with the voltage regulator removed,but if i install the voltage reg, and put my test light on the stud i get a pulsing power .

Just checked the nuts on the back of the gauge, they are clean,and i just snugged them up a bit more,still no reading. I will bring home a meter today to check readings that were mentioned above.

I dont know if having no power at the instrument fuse on the fuse box could be causing anything. I found a pink wire that has been cut .

I'll have to check the schematic to be sure, but if the center VR terminal is getting 12V steady, that's all the fuel and temp gauges need to operate.

The VR needs a load to begin pulsing. Since the temp sender is disconneced, the load must be the fuel sender, unless there is a short circuit somewhere.

When you get the volt/ohm meter, make the resistance measurements as described above, and verify with the voltmeter that 12 VDC is at the center terminal of the VR.

If you MOMENTARILY connect the output side of the fuel gauge (threaded stud) to ground, the gauge needle should move toward full. If you keep the gauge grounded for more than 5 or so seconds, the gauge will burn out. Once the needle reaches near the full mark, remove the short immediately! It is safe to ground through a 10-50 ohm resistor.

Ok the dash thats in the car and all hooked up shows 39.0 ohms from stud to stud.

The dash thats on th bench ( my orginal dash) shows 12.7 stud to stud.

I tested the dash in the car with the battery disconnected.

That might be the problem right there - burned out or otherwise defective fuel gauge. I would put the 12.7 ohm gauge in that dash.

I also highly recommend the 5 volt solid state gauge voltage limiter. With this device, shorting the gauge output to ground won't destroy your valuable gauge, like the pulsing stock original VR will.

You can do this mod for < $5.

i know this won't cure the fuel gauge problem but if i remember correctly the tan wire and instrument fuse won't be hot all the time, only gets power when the lights are on.

Ok, i will try putting the other gauge back in. Just strange becuase it did not work before. will keep you guys updated,thanks for the help!

IT WORKS!!!!!!!!!!!

Took my original gauge put it in the cluster i purchased that had the bad fuel gauge. Must of been the circuit board on my old dash that was bad? Only thing now is I have no dash lights at all. Could that happen if my dimmer switch is bad? If I turn it all the way my doem light goes on...

I did notice a Heavy PINK wire out of the main dash harness is cut. Then more towards the right side of the dash there is smaller pink wires with mutliple spade connectors(from the factory) but it doesnt look like the heavy pink could connect to the smaller pink wire. ahhh..the fun goes on. Thanks for the info on testing the gauge though!!!

could be a bad dimmer. but when you get the dome light, dash lights should come on full as well. Or at least that is how I remember it working. So you would have to trace from the plug to th dash and see what wire powers up the lights. trace the circuit board back from the light holes to see what plug needs power. Should go back to the dimmer and head light switch.

Ok well i now have power to the 2 most right side lights of the dash. When i put the headlight switch on it powers the instrument lights(orange wire) .

Dimmer is pretty useless but i believe it is working. Now its probably either a bad circuit board or the light sockets them selves.

I have a factory clock also, the wiring diagrams say that its a gray wire . I looked on my harness in the car and a spare harness and i do not see a gray wire anywhere.

The gray wire to the clock comes off the fuse block. Fourth fuse from the left, I believe. However, if your car originally did not have a clock, the wire won't be there.

Ok great info. is this just a regular 12v power wire that has batt power?

Yes, it must be a 12 volt feed, with 12 volts all the time. Play it safe and make sure its fused - just in case.

And don't rely on that clock for meetings, doctor appointments, or job interviews. You will never be on time.