jsheehan

My car is a 2005 V6 mustang with the standard gauge cluster. I've been having a problem for a couple of weeks where my speedometer has been acting up. I will start the car and be driving along, and then will look down and notice my speedometer is off by a lot (It'll be at like 20 when I'm going 60 or so, but this can vary). It is never off by a consistent amount and it only seems to happen when it's really hot outside. When I stop, the speedometer gauge drops bellow 0. When I shut the car off and come back later after it has cooled down outside (usually at night since I live in Florida and it is hot here all the time in the summer) the speedometer goes back to working fine. All the other gauges are working fine. Anyone know what might be causing this before I decide to gamble taking it to the dealer and them not being able to figure it out (or even reproduce it since it only happens intermittently)?

Andy&RobinGT

We're having the same issue...we have a 2005 GT. The issue started off with the guage not reading correctly...sometimes showing 80 mph at idle. Now the needle is dead...reading below 0 and won't work at all. We've checked all possible fuses etc. Any help would be much appreciated!

tom281

Seems to me like maybe there is some kind of sending unit either on the transmission or somewhere that might not be functioning properly. Unless the computer is factoring mph based off engine speed / load then something must be telling the gauge how fast the car is going. This is the first that I've heard about this kind of problem, sorry I'm not much help.

05YellowGT

I posted about this a month or so ago. One day I had just accelerated getting on to the interstate and noticed my speedometer said I was doing over 100 MPH. Then it wouldn't drop below about 40 MPH , even when stopped. I have the Aeroforce scan gauges and I pulled up my speed and it was correct , so the computer actually knew the correct speed. The next day it started out still off , but eventually correct it's self and didn't happen again. Then last week , my fuel gauge suddenly started registering low and I checked the scan gauge for the fuel level and it was correct. In both cases the computer knew the correct reading , but was sending bad info to the instrument cluster. The computers are very sensitive to any change in the electrical circuits and will do some strange things. I had an after market alarm go bad and it caused the computer to think that the key was in the start position and would turn the starter over every time I pushed the clutch in , even if the key wasn't in the ignition. I remembered I had tapped in to a wire on the instrument cluster for power for a gauge , so the first thing I did was to disconnect that and it hasn't happened again. Then I also remembered a thread about leaks on the passenger side causing the computer to do strange things and when I checked this weekend sure enough I have developed the leak. So I think it was a combination of the leak and the changes in the electrical system that caused the computer to send bad information the cluster ...

Menace

Anybody figure this out yet? My wife has an 05 Mustang and the speedo is always way off. We can be stopped going over 100 on the speedo.

Thanks

05YellowGT

Do you have the water leak in the passenger side foot well that usually accompanies this problem ? I had the leak fixed , at least I think so but since it hasn't rained hard since then I can't be sure. At the time the dealer fixed the leak , they were supposed to look at the gauge problems , but they said they were functioning properly. However when I picked the car up , both the speedo and the fuel gauge were off. The next morning the speedo was correct , but the fuel gauge has been wrong intermittently since then. Has anybody else had the leak fixed , what did the dealer do about the gauges ? Is there some corrosion on the SJB or the fuse box that is causing the problem ? I know these computers are very sensitive to any voltage changes and will do strange things , so I assume that's what the problem is. I have the aeroforce scan gauges and they show the correct fuel level and speed , so I know the computer knows what the correct readings are. I assume it's just not sending the correct values to the gauges ...

Indystang

I had a similar type of problem and the dealer replaced the cluster under warranty. I think its the whole guage package. Been fine ever since

05YellowGT

Indystang , so you had the problem without the water leak ? I've been assuming it was related to the leak causing the computer to weird out , but maybe not ...

SD CALSPCL

I will dating myself, but..in 1974, I purchased a new Mercury Capri. It had an electronic dash package. All the gauges were mounted on a circuit board. while driving across country, on a military transfer, the speedo started acting up, then the fuel gauge, etc.,just as all of you have described.

I stopped at a Ford dealer, and they diagnosed the problem as a hairline crack in the circuit board, which opened up when the temperature in the car got hot. They didn't have the dash cluster in stock, so I just drove to my destination and had the cluster replaced under warranty. No more problems. Sounds like your dash clusters are the problem. Hope this is helpful.

Indystang

Yes I dont have any leaks and only had the speedometer and fuel gauge problem that one time. THE REPAIR SHEET SAID "REPLACED CLUSTER". The fuel gauge would read empty with half a tank of gas. Even when filled it still read only 3/4. I also had a high sullfer check engine light too that caused a wrong reading but the cluster fixed everything else. Chevron Techron in the bottle cleaned up the sulfer problem and the dealer did that for free.

05YellowGT

Thanks for the info , I know the leak will cause the computer do do strange things and I thought this might be one of them. Knowing this makes a little more sense , since it's still doing it after the leak was fixed ...

flame312

I have a 2005 GT 5 speed with 19000 miles, it has gauge problems also. First tach went out, then speedo went 5 to 25 mph slow, then temp gauge went high, and fuel gauge finally went half inch past full. Now everything is working except tach and speedo. Mine is out of warranty so I am trying to avoid going back to the dealer. Any help on fixing this myself would be great....

flame312

Also, I forgot to add that I dont have the leak on the passenger side that 05yellowgt was asking about. The tach and speedo work sometimes but not often. I am thinking about taking the cluster out and looking for loose connections or problems with the circuit board. Has anyone done this? How hard is it? What are the pitfalls? Thanks for any ideas.....

05YellowGT

At this point I no longer think the problem is related to the leak. One of the first things I did was pull the cluster and make sure the connector was on good and tight and the connections were clean. Currently my speedo is correct , only the gas gauge is wrong. I have scan gauges and the readings from the computer are correct , so it pretty much has to be the cluster. I'm also out of warranty , so I'm stuck with paying for it when I decide to get it fixed. Since I have the scan gauges and know what the actual readings are , I can live with it for a while. When I do it I may upgrade to the GT500 cluster , I'd like to have the tack on right hand side ...

azoufan

If you can, pull the cluster and open it up and feel the needles. They should rotate pretty smoothly. I have this problem with my tach and fuel gauge and those needles definitely have a lot of resistance behind them. So for mine, the gears inside the tach just don't have enough power to turn the tach and the fuel gauge properly, which is why mine is way off. Just wondering if others are having the same problems, my bet is that it's the same. My computer always reads the correct fuel consumptions, miles to E, etc. but the gauge is never even close, mostly points straight down to the floor. My tach registered what would have been about 13K RPM on the way home, so either it's broken or I am a race car driver.

flame312

Thanks for the help. I am going to pull my cluster as soon as I get a chance and hope for a loose connection. Thanks for the suggestion azoufan I will check the needle rotation also. If I find anything suspicious I will post it asap. In the mean time I will be checking back here. If anybody comes up with a solution please post or if anybody just has any tips for removing the dash to get to the cluster I could use some pointers. So far all I have seen are two screws at the bottom of the panel below the steering wheel, I guess that is a start, I am sure it will be uphill from there......

azoufan

Going from memory here, but basically the trim rings and dash piece in front of the cluster just pulls out towards the steering wheel. Then there are 4 screws / bolts that hold the cluster in place. Pull the cluster out and it's just one connection to remove for the harness. Take the cluster inside and the plexiglass snaps off, I think it's held on by 4 tabs or so. The entire removal process takes 3 minutes tops. If you end up moving the other needles around too, just note where they are when the car is on at idle and when turned off. I used a digital camera the first time just to be safe.

It's really really easy to do, nothing to be nervous about at all. Installation is the reverse of removal, easy cheesy!

05YellowGT

It's easy to remove , lower the steering wheel to it's lowest position and just grab the outside of the tach and speedo bezels simultaneously and pull. It's just held on with clips and will pull off easily. Then there's 4 bolts that hold the cluster in place , remove those and pull it out so you can get to the back. The harness plugs into the back and once it's unplugged the cluster is free ...

flame312

Thanks guys, thats sound like it is something I can do. It helps knowing what I'm facing. I'll like the camera idea, that's a good tip. I'll get on it as soon as I get a chance and let you know what I find.

Mxyzptlk

Today I came outside (30 degress out) and started up and the speedometer moved all the way over to 120. It moved up when I drive and points straight down when Im going 60 but when I stop its back down to 120. Still there when the car is turned off.

Is there a sensor to check or is this a failed cluster. Piece of shiit carrrrr