fuel and temp gauges?

[hotrod ford]

i changed out my stock gauge for a f600 gauge today looks good. with the stock gauge the oil, temp and fuel would not work so i thought it was the gauge or the fuse. changed all the fuses and replace the gauge and the fuel reads 1/4 of a take when i know it is full right now and the temp won't read at all. i remember reading somthing a year or so ago about this type of issue but can't remember what it is to fix it. does anyone know?

[Happy_Camper]

It could be a few different things, but here's a couple of common ones to check.

With the key turned on, disconnect the wire at the temp sender, and connect it with a jumper lead to a real good ground. If the gauge goes to full hot, it's the sending unit. If it doesn't, set your volt meter to the lowest scale that will allow you to read 6V. See if there is 5V between the wire at the sending unit, and the ground. If not check the connections and wiring. Also there should be a voltage regulator that takes battery voltage down to right about 5V attached to the back of the gauge panel. This is the voltage the gauges runs on. If the output voltage is low, it will cause the gauges to read low. The original unit will fluctuate up and down, but should average 5V. They make a solid state replacement unit that works great, and is available through companies like National Parts Depot (www.npdlink.com).
Hth,

[fordman]

so you got the wires all hooked up correctly? that is my first thought since so many gauges arent working. but on the backs of ours is a ipvr which can be adjusted for the fuel tank gauge. i think the f600 cluster should have that as well. the ipvr can affect all of the gauges when it is adjusted.

[hotrod ford]

yep, all the wires are hooked up right. it's funny to me that both gauges read the same. no temp and the fuel reads 1/4 of a tank. that tells me it's not the gauge. i had heard about somthing on the back of gauge panels before but could'nt find anything that can be adjusted like that.

[fordman]

this is what it looks like . it should be there.

[hotrod ford]

ok, that is on there but how can you adjust it?

[fordman]

a small screwdriver i have been told. i have never done it.

[hotrod ford]

i just have two terminals on there?

[fordman]

thee should be a third place as to where to adjust it from what i have read and been told. this is an example of what the third hole looks like. unless it just doesnt have one. i do not know if they made adjustable ones and nonadjustable ones or not. http://cgi.ebay.com/ebaymotors/1971-91- ... ccessories

[fordman]

well mayeb they do make nonadjustable ones. http://cgi.ebay.com/ebaymotors/1967-68- ... ccessories

[hotrod ford]

ok, here is what i did today. i did find that little screw and turned it both ways and nothing happened. i also took out the temp sensor and ran a wire to the positive terminal on the battery. if it was bad the needle should have pegged all the way to the right but did not. i check all the wires again to verify that they are correct and are. i looked at every wire in the truck to see if there are any broken, loose or grounded. i have no clue why the 71 or f600 will not read right.

[70_F100]

You may have just fried your cluster.

The wire to the sending unit operates off GROUND (negative terminal), not POSITIVE!!!

Try it again, just this time GROUND the wire to the sender!!!

[hotrod ford]

i believe i'm putting to much thought into this. does the temp sensor even have to come off of the engine or not to test it. if not, what exactly am i checking? the sensor or the sensor wire? i have two wires on the gauge. a red/white one and a black/white one. the one that is on the sensor is red/white.

[70_F100]

Just ground the wire to the sending unit.

If you ground the sending unit, you've accompished nothing. The unit is grounded when it's installed.

Grounding the wire is the quickest test to determine whether it's the sending unit or something in the temp gauge circuit.

The sending unit is variable ground, changing with the change in engine temp. The hotter the temp, the higher the resistance. Thus, grounding the wire provides highest resistance, making the gauge rise.

[hotrod ford]

Just ground the wire to the sending unit.

If you ground the sending unit, you've accompished nothing. The unit is grounded when it's installed.

Grounding the wire is the quickest test to determine whether it's the sending unit or something in the temp gauge circuit.

The sending unit is variable ground, changing with the change in engine temp. The hotter the temp, the higher the resistance. Thus, grounding the wire provides highest resistance, making the gauge rise.

when you say gruond the wire to the unit, are you talking about the wire that runs to the gauge? do i need to stick an extra wire in the terminal and ground it on the engine somewhere?