I have a 1995 ram 1500 and i dont know whats going on with the gauges. the fuel gauge after 15 gal will read empty and when i fill it up, it goes up to between 3/4 and full. it also reads 10 miles faster than the truck is really going. i have stock size tires. i had the trans replaced but it was doin that before i replaced the trans. i was thinkin ill just get a new cluster. but i want to make sure. any ideas?

 

if both of them happend at the same time then you need a new cluster, if they'er months or years appart then start with your speed sensor on your rear differential and make sure your wiring on your fuel pump is not damaged

 

As far as the fuel gauge, I don't think you'll find anyone in here whose gas gauge isn't either perpetually off or at least malfunctions from time to time. Mine often starts reading E and dinging after only 200 miles and when I go to fill up my 34 gallon tank it only takes around 25-26 gallons. I guess I just have an 8 gallon reserve.

 

Sounds like there's an offset in the actual vs. what is displayed thus meaning, it's out of calibration and / or tolerance. We are talking about electronic / digital dash displays and not analog gages correct?

If it was just a bad fuel pump reading, that's normally associated with a problem with the sending unit at the pump level. It is a wiper type pot that sends x-amount of voltage to provide the reading and, for every volt correlates to either an analog movement of a needle such as in my 96 or, on later vehicles, it is a digital display. But, in either case, there's error in the scale that throws the display out of whack.

Sometimes, in extreme cold, the temp changes the value of the electrical components thus throwing the voltage readings out of whack thus why the gages read incorrectly.

In your case, you have two gages that are out of whack indicating a possible common link. It may be a common supply that feeds the cluster or, it may be the cluster itself. It's hard to say exactly what the root cause for that is.

One thing to do here would be to look at the schematics and note what CKTs are common to both of those gages along with noting the supply voltage to those CKTs as well.

Then from there, you start measuring things and start to rule things out one at a time.

CM

 

Has it always read 10 mph off since you've owned it or is that something new? If it's been that way perhaps the previous owner had larger tires and had replaced the speedo gear.

I think you've got a bad sending unit.

 

There are no digital gauges on a 2nd gen. And he meant gauges.

 

sorry. i should of explained it alittle better. the gauges, fuel and speedo, both were reading wrong when i got the truck a yr ago. ive been fixin it up since i got it. the guy that had it before me didnt take care of it and used it as a landscaping truck. so slowly im tryin to fix everythin. when the gas light turns on, i used 15 gal. they r regular gauges. nothin special. not lifted, yet. stock tires 265/75/16. i was just gonna replace the gauges but i dont want o throw money into somethin i dont have a problem with until i get certain things takin care of. when i bought it, he had 225/75/16 but then the truck was 10 miles off to.

 

Get used to the gas gauge, they are a common problem. I would have the dealer recalibrate the PCM for your tire size/gear ratio. Sounds like it was messed with or something is not as it was when new.