Gauges don't work? updated 4.04

[terry1167]

My oil gauge and temp gauge now works. Is the alt gauge supposed to move at all, while the truck is running or not? MIne just stays in the centerWith the ignition switch on, regardless if running or not? My fuel gauge is still not working. Both of these gauges (fuel and alt) are located on the left side of the cluster....coincidence?

Also, I'm sure this is a dumb question but......per the tech article "remove the wire from the fuel tank sending unit and ground it to the unit housing.", exactly how do I do that? I am assuming it is referring to the orange wire that has the black boot attached to the end. Would I remove the black boot (cut it off) and then ground it or ?

Thanks for any help on this!

[fordman]

most of the alt gauges seem to never move. some others do move a little. just grab the orange wire's black boot and pull it off the sender. and stick a bolt in there and ground the bolt to the cab.

[terry1167]

most fo the alt gauegs seem to never move. some others do move a little. just grab the orange wire's black boot and pull it off the sender. and stick a bolt in there and ground the bolt to the cab.

Ok, thanks Craig. Ok, did it and nothing. If I am confident that the gauge works and power is going to the gauge, then per the tech article, it would be the orange wire to the sending unit? Must be something wrong with it?

[fordman]

if no the answer reads : The power supply to the gauge has been interrupted, (check fuses), the gauge is defective, or the wire from the gauge to the sending unit is open or has a break in it.

you can check for wire continuity by testing the wire at both ends to see if it is in tact with a volt meter set to ohms. if the needls moves on the volt meter the orange wire is good. if the wire is good then check the fuses if that is good and has the flashing power through the orange wire to the sending unit. the gauge is bad. you can check the guae by powerign up the ipvr and grounding the other side of the gauge.

[Thunderfoot]

Hey Terry,


From your PM you said that you have a Tank Selector Switch and 2 tanks, which is some good info for us as the switches do go bad. here is some more things to try to isolate your fuel gauge problem and a couple things to check for the Alt gauge.

Glad your oil and temp are working,

From your test for the fuel:
The gauge worked in the instrument panel by grounding the sense connector on the gauge and it pegged over to full. = the instrument gauge is good
Grounding the Orange wire at the fuel sensor (sending unit) did nothing, but you said you have a full gauge switch = 2 tank setup on your truck. I would look at your switch (they do go bad) if you look at the wires going into the switch it should have 3 orange wires going into it, take some tape and mark them 1,2, and 3 for a reference and location on the switch. Then unplug them and try grounding each one with the key on to see if one of them makes the gauge move (it should be the wire in the center of the switch)... If one of these wires makes the gauge move then your problem is probably the switch, but you can take and use a piece of wire to jumper this wire over to one of the other wires and then see if the gauge works... You might also have to ground the wire at the sensor to confirm that the wire is good, just in case the sending unit happens to be bad too... This will tell if the wire is broken somewhere, either between the switch and sending unit or problem is from switch to gauge (if you don't get any wire to make the gauge move), or if it is just the switch is bad.

On the Alt gauge;
They usually will only move a little over a needles width in either direction... in the + direction if you have a good charged battery with the engine running and the headlights on and with the engine off and the head lights on it will move in the - direction about the same. They are really not very good as they don't move very far... If it doesn't move at all then there are 2 inline fuses, one by the starter relay and one closer to the alternator that one is on a Red wire and the other is on a Yellow wire check to see if those fuses are good and making good contact in the holders.

Let us know what you find out on the fuel switch.

[terry1167]

Thank you Fordman and Thunderfoot for all of the help so far. I unplugged the dash fuel tank switch and unplugged the 3 orange wires. Grounded each and no gauge movement at all. The gauge did peg when I bench tested it like Fordman did so I assume that the gauge is good. I also tested the IPVR and grounded the gauge and it again pegged. Even if the orange wire between the sending unit and switch was bad, I assume that by unplugging it at the switch, it would have made the gauge move. So per Thunderfoot's email, it looks like it might be the wire from the switch to the gauge? Does that sound right?

[Thunderfoot]

Yes, it sounds like it is either the wire or the other would be a broken trace in the circuit board or the connection of the connector on it. To test this I would take a short piece of wire (striped on both ends) and with the instrument cluster pulled out but still plugged in, place the wire in the connector where the orange wire is going in making contact with the wire terminal in the plug, and then the other end to the bear metal dash and see if the gauge pegs. This will tell you if the problem is between the gauge and connector (circuit board) or if the problem is in the wire from the connector to the selector switch.
If it didn't move the gauge doing this, then try putting the wire on the trace part right by the connector for this orange wire, this will help tell if the problem is the connector or the trace it self...

Hope that makes sense...

[terry1167]

Yes, it sounds like it is either the wire or the other would be a broken trace in the circuit board or the connection of the connector on it. To test this I would take a short piece of wire (striped on both ends) and with the instrument cluster pulled out but still plugged in, place the wire in the connector where the orange wire is going in making contact with the wire terminal in the plug, and then the other end to the bear metal dash and see if the gauge pegs. This will tell you if the problem is between the gauge and connector (circuit board) or if the problem is in the wire from the connector to the selector switch.
If it didn't move the gauge doing this, then try putting the wire on the trace part right by the connector for this orange wire, this will help tell if the problem is the connector or the trace it self...

Hope that makes sense...

I picked up an instrument cluster from the JY this weeked from a 71 bump. I plugged the connector into mine and all of the gauges worked EXCEPT the fuel gauge so this tells me that the problem is somewhere in the wiring between the sending unit/sensor and connector....right? I bench tested the gauges a while ago and they all worked. I did as Thunderfoot suggested and tried testing the wiring to the main/auxiliary switch too. I tested the fuse panel and all is good. Soooooooo, I guess I need to try and find the break in the orange wiring. I can't think of what else it would be. If anyone has any other suggestions, feel free to let me know. Thanks for everyone's help!

[fordman]

when checking wires for continuity. i tak my volt meter and set it to ohms. i then touch each end or the wire with each electrode. if the meter pegs out or moves at all. then the wire is intact. when i say moves at all. is because sometimes it gets hard to hold the meter and two electrodes to two other wire ends.

[terry1167]

when checking wires for continuity. i tak my volt meter and set it to ohms. i then touch each end or the wire with each electrode. if the meter pegs out or moves at all. then the wire is intact. when i say moves at all. is because sometimes it gets hard to hold the meter and two electrodes to two other wire ends.

Thanks Fordman. I'll give that a shot and hopefully I can go through this exercise with my volt meter this weekend.