I m having problems with my fuel and temp gauges , I recently bought a 1979 f150 4 wheel dr . when you turn the key on the gauges peg all the way over , as in full of gas and full hot . I guess theres a hot wire some where causing this. Could it be the circuit on the back of the gauges ? Any help would be appreceated ! thanks

 

Welcome to the site !

May I suggest you come to the forum related to your truck ?

That would be the 73-79 truck forum.

We will answer your questions there


Short answer : pegged gauges means the signal part of the gauge system is getting a direct ground.

 

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Thread moved to Electrical Systems/Wiring forum.

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I am assuming they stay over there all the time. Sometimes guages will do a little dance when first starting and then settle down and read correctly. So if they stay over there all the time, it's suspicous that they are all doing it.

Just as a test, and something easy to do, would be to find the water temp sending unit out on the engine. This should be a red/white wire going to a sensor on the engine. Take the red/white wire off the sensor, and with the key in run, ground the red/white wire to the engine block. The temp guage should swing full scale one direction(ground may be to the right at hot so it may not move). The take the red/white wire off the engine block, and let it hang in the air, touching nothing. The temp guage should swing full scale the opposite way. If it passes this test, the guage and the wiring are ok.

You can try the oil pressure guage too. Do the same thing as above, only the wire for it is white/red.

If both of these fail the test, then there must be something going on with the instrument cluster. You can pull it apart, and check for loose wires and such, and take a pencil eraser and clean all the copper connections.

You can also test the fuel guage as above, only it's a little bit harder to get to back at the gas tank. It's a yellow/white wire.

 

I joined this website looking for info on my truck , its very obvious that this website was put to gether by a computer geek ! well I dont have a masters in computer science and dont want one . I hate this website not for its content ,but because its to complicated. Ive never heard of a thread , why should learn this @#$%% just to talk about trucks ! All a person should have to do is pull a web site and ask a question , push submit , and get an answer , let everyone see it , these things arent a secret , thats what a forum is about . shut this over complicated website down and put up something the average person can use !

 

Ummm...ok?

You came to this site to get an answer to your question. You posted in the wrong forum so I moved it to the correct one and welcomed you. If this it too complicated for you, maybe you should have asked for some help (like I invite you to do in my welcome post) and then you can learn.

This site is not complicated. Sure, it may take a while to get used to but if it was REALLY complicated then we would not have some many users. There are no secrets on here. If you can just post a question anywhere you want then the site would be in chaos. We like to keep it organized so other people can find answers if they need to.

Now, if you would like we can try to help you. If not, well, see ya later.

-Matt

 

Roy two things, look around a bit and you will see just how BIG this site is.

second Beast and Franklin2 are what you call moderators on this web site, they help with keeping order and ensuring thing goes smoothly on this very very large web site,hence the title under their names and they are trying to help you. so how about you read 'read' Beasts first post.

 

The problem you are having with your gages is very common and has been discussed here many times. It is caused by a faulty ground on the instrument panel voltage regulator. It is a small metal part with terminals like a 9V battery on the back of the instrument cluster. The ground is usually bad where it is mounted on the flex circuit. Cleaning the contact surfaces and coating them with some spark plug grease then reconnecting will solve the problem 95% of the time. Sometimes a new regulator is required.

The instrument panel voltage regulator:

 

I have the same problem on my 1989 f350 7.3l 4x4. I do not have the instrument panel voltage regulator as shown. I did replace the circut board though. I will try testing the lines, though I must admit, I am not looking forward to messing (or trying to find) with the wiring for the fuel tanks (since I have 2).








I found this thread on page 36, way back in the woods. Proves that if you shut up and search on a site as large as this...... you will probally find your answer.

B6-resurrecter of dead threads

 

The Instrument Cluster gauges include the following: Fuel, Oil, Temperature, and Tachometer (optional). Each gauge consists of a coil, a magnet and a pointer, which moves in direct proportion to the output of its sender.
Fuel Gauge and Fuel Gauges Sender
The Fuel Gauge Sender's resistance controls the magnetic Fuel Gauge's pointer position. The Sender has a resistance of 145 ohms when the fuel tank is full and 22.5 ohms when the fuel tank is empty.