Gauges don't work? updated 4.04

[terry1167]

None of the gauges work in my 72 F250: gas (both main and aux), Ammeter, oil pressure, engine temp. However, the speedometer works but when it's real cold out, it takes a few miles before it works. The cluster lights and blinkers also work. I did the fuel sender unit test (per tech article) to see if the gauge would move and nothing. I checked all the fuses and they are good. I removed the instrument cluster and disconnected the speedo cable. The cluster and area behind it ws was very dirty/dusty but the circuit board and connections did NOT look corroded. The wiring looked "good", meaning that it hadn't been hacked up. Everything looked intact and tight.

Any ideas of where to start before I buy new gauges or a complete new wiring harness?

Any advice is appreciated.

[fordman]

sounds like the ipvr is bad. are you gettign the flashes of power from it? if not it could be bad. or the circut board on the back of your cluster could be the problem. i would see if you are getting power to the ipvr from the circut board. if you are the ipvr is dead. if not then move back to where the power comes into the circut board and see if it is giving power to the board. if not then check the fuse panel.

the speedometer probably has some built up grease inside fo the cable. remove the center and clean it as well as the inside of the cable with some sort of grease desolver.

[terry1167]

Thanks Fordman......probably a dumb question....what's a IVPR?

[fordman]

Instrument Panel Voltage Regulator. figure 5 and 7 on this page. http://www.fordification.com/tech/fuel- ... -units.htm

[terry1167]

Instrument Panel Voltage Regulator. figure 5 and 7 on this page. http://www.fordification.com/tech/fuel- ... -units.htm

Gotcha....thanks for the tip. I'll have to take a look and check it out.

[terry1167]

Hi, I am still trying to figure out why the gauges don't work. I've tested the fuse box (ends and back) and all have power. I replaced the IPVR. I've tested the "connector" that plugs into the cluster and have a question, probably a dumb question but I do not profess to be much of an electrician. Are ALL of the connectors (that have the copper inserts) within the plug supposed to have power? I've tested each of them and most have power....blinkers, dash lights, truck lights, etc. but a few of the copper slots do not have any power. I am trying to make sure that all the power is coming through. I haven't yet tested each gauge. I tested the fuel sending unit and the gauge did not move. I find it hard to believe that all of the sending units and/or gauges have failed so I am assuming that it is something to do with the power. It could be the circuit board. Thoughts about the connector or ideas of what to do next?

Thanks for your help.

[fordman]

i have been testing two clusters myself right now. from a 71 and 72. mine has full gauges. what i did was out on the [censored] counter. i hooked up a power wire directly to the ipvr. on the inner post. that is the incoming power. the outer one is outgoing power. then what i did after that was to ground one side of the fuel gauge water temp gauge and the oil gauge. all of them pegged out. so that meant i was getting power through the ipvr and the circuit board. all the way to the gauges. and that the gauges were also good. i was also able to hook up a fuel sending unit and move the arm up and down and watch the gas gauge slowly move when the arm was moved. the ipvr will output 5 volts of flashing power into the circuit board. it has 12 volts coming in to it. here is a picture of the incoming side of the ipvr. the one i am pointing at. if you have power coming in for sure and 5 volts of flashing power coming out. flashing means it will come and go like a blinker will blink. then the problem would lie with the circuit board not providing power to the power side of the gauges.

the connector you show in the picture wont have power at every single wire. i think it may only have one 12 volt source incoming and then the dash lights and blinker lights will also have power when turned on. at least 3 of the wires in the plug and just sensor wires. so they only carry a signal of ground i think to the circuit board and then onto each gauge.
from looking at your picture the only wires that will o May have power when the accessories are on. will be the blue with white stripe the blue with red stripe. and the main power wire in the left hand side of your picture. and then somewhere will be the wire for the alt gauge. i think also in the left hand side of that picture.

[terry1167]

[quote="fordman"]i have been testing two clusters myself right now. from a 71 and 72. mine has full gauges. what i did was out on the [censored] counter. i hooked up a power wire directly to the ipvr. on the inner post. that is the incoming power. the outer one is outgoing power. then what i did after that was to ground one side of the fuel gauge water temp gauge and the oil gauge. all of them pegged out. so that meant i was getting power through the ipvr and the circuit board. all the way to the gauges. and that the gauges were also good. i was also able to hook up a fuel sending unit and move the arm up and down and watch the gas gauge slowly move when the arm was moved. the ipvr will output 5 volts of flashing power into the circuit board. it has 12 volts coming in to it. here is a picture of the incoming side of the ipvr. the one i am pointing at. if you have power coming in for sure and 5 volts of flashing power coming out. flashing means it will come and go like a blinker will blink. then the problem would lie with the circuit board not providing power to the power side of the gauges.

Thank you very much Fordman. Exactly how does one "hook up a power wire" like you mentioned. I know what you meant but I'm not sure how you go about doing that? Also, exactly how do you "ground one side of the gauge"? Thanks as this is very helpful.

[fordman]

i was using apower supply in the house wire a bare wire coming off of it. i stuck the wire inside of the hole in the ivpr. where my finger is pointing at. while that was hooked up i used the ground side of the power supply to the threads on each gauge. i tested each one individually. one at a time just movign the ground wire from one gauge to the other.

[terry1167]

i was using apower supply in the house wire a bare wire coming off of it. i stuck the wire inside of the hole in the ivpr. where my finger is pointing at. while that was hooked up i used the ground side of the power supply to the threads on each gauge. i tested each one individually. one at a time just movign the ground wire from one gauge to the other.

Fordman, I've tested the gauges and Ipvr with a 9v battery like you advised. The gauges all pegged so I assume the gauges are operational and good. Same with the Ipvr. That seems to work per your method above with hooking the battery to the inside/incoming post of the Ipvr. I used one of those circuit tester pens that light up when it senses a power/hot wire and tested the cluster connector, fuses, fuse panel, and they all seem to work (it lit up). I tested the orange wire to the fuel sending unit with the pen light and it did NOT light up. So.......would it seem logical that the problem is the circuit board? Would that also explain the lack of power going to the orange wire of the fuel sending unit? I don't know what else it could be?

[fordman]

the orange wire isnt a power wire. its just a sensor wire. 1 power wires goes into the plug. you may also find a second wire that i shot for the alt gauge. the rest of the wires are just sensor wires. in and out the power is all in the circuit board and ivpr once power comes in from the plug to the circuit board.

[terry1167]

the orange wire isnt a power wire. its just a sensor wire. 1 power wires goes into the plug. you may also find a second wire that i shot for the alt gauge. the rest of the wires are just sensor wires. in and out the power is all in the circuit board and ivpr once power comes in from the plug to the circuit board.

So looks like it is most likely the circuit board since the ipvr seems to be operating....at least that's my guess? I'll probably have to research where to buy a new one, perhaps from LMC or DC or Mac's. Is there any trick to installing a new board or is it pretty simple?

Thanks again for the help.

[fordman]

installation is easy. i have a used board for a 71 /72 with full gauges.

[Thunderfoot]

I might of missed it in your posts but if you take the sense wires at the sensors (water, oil, and fuel) and unplug them from the sensor and touch the connector to ground the gauge will peg like you did on the instrument panel test, this will tell you if the wire and circuit board are good if they peg out and that the sensor is bad.

All the Sense wires (Orange-Fuel, White/red striped-oil, and Red/white striped-water) should have a pulsing power on them with the key on... If you don't have this power on these wires check the pad on the circuit board where the connector makes contact for power to see if it has power there, it is a common problem with these circuit boards for the pads to get dirty and make bad contact, you can clean them with a pencil eraser. Also you can usually see if the trace in the circuit board is bad by a visual inspection of it. Here is a picture below of my F600 cluster that had a broken connection that I did a quick (not so pretty) fix on. If you have power on the connector pad then check that the wire is making good connection to the connector pin and that the pin is making good contact with the circuit board pad.

For the Amp gauge; both the red and yellow wires for the Amp gauge should have power on them all the time (key on or off), there are in-line fuses in the wires by the alternator and starter solenoid for these wires.

[terry1167]

installation is easy. i have a used board for a 71 /72 with full gauges.

Thanks Fordman. That makes me feel a little better in the event that I do need to switch out the circuit board. I tend to dive in and then totally "screw it up".

I might of missed it in your posts but if you take the sense wires at the sensors (water, oil, and fuel) and unplug them from the sensor and touch the connector to ground the gauge will peg like you did on the instrument panel test, this will tell you if the wire and circuit board are good if they peg out and that the sensor is bad.

All the Sense wires (Orange-Fuel, White/red striped-oil, and Red/white striped-water) should have a pulsing power on them with the key on... If you don't have this power on these wires check the pad on the circuit board where the connector makes contact for power to see if it has power there, it is a common problem with these circuit boards for the pads to get dirty and make bad contact, you can clean them with a pencil eraser. Also you can usually see if the trace in the circuit board is bad by a visual inspection of it. Here is a picture below of my F600 cluster that had a broken connection that I did a quick (not so pretty) fix on. If you have power on the connector pad then check that the wire is making good connection to the connector pin and that the pin is making good contact with the circuit board pad.

For the Amp gauge; both the red and yellow wires for the Amp gauge should have power on them all the time (key on or off), there are in-line fuses in the wires by the alternator and starter solenoid for these wires.

Thanks Thunderfoot for the advice. I'll do a little more research on this and give it a try. I feel like I'm close to figuring out the problem but close doesn't quite solve the problem! But the advice I've gotten from y'all,has been huge. I really didn't know where to start.
Thanks and I might have some more quetions as I get even closer.