Cluster problem? Ideas?

[Everdream]

Having the following problem with my instrument cluster:

Tachometer Stuck at 3200RPM(ish) while running) moves up but not down.
Fuel gauge not working.
Low Oil pressure all the time (about half way up, never moves, even after a oil change)
Engine always says its about a 1/4 over in the cold zone.
these all "return" to their correct zones when the truck is off (the fuel gauge moves up to about 1/4 with the truck off)

Where does this tach get all its information from? Replaced with new gauge cluster, same symptoms. speedo works fine.

I don't know where to go with this problem, Id like my fuel gauge to work, and I'm hoping its not the sending unit in the tank, im leaning towards the wiring to the gauge itself because of all the other gauge problems.

thx guys

1992 Ford Explorer XLT 4.0L Automatic 4x4.

 

[Roadrunner777]

(duplicate post)

 

[Roadrunner777]

There is a known issue where a bad solder joint on the tach circuit board causes the tach to sit at around 3,000 rpm. You have to remove the entire gauge cluster to get to the flex circuit. If you replaced the entire gauge cluster, meaning all the gauges and flex circuit, then you need to know where the tach lead comes from, and I think it is the coil pack. Check there for splices and issues, a lot of times a remote starter gets spliced on this wire. Here is a link to the circuit board issue:

http://www.explorerforum.com/forums/showthread.php?t=275462&highlight=tach

The oil pressure behavior you see is normal, at least it is the way it was designed to work. The good news is that your oil gauge can work correctly, but you will need a different sender unit and you will need to short a 20 ohm resistor on the same flex circuit as above. Read this thread, it is long, but the good stuff begins around post #9.

http://www.explorerforum.com/forums/showthread.php?s=&threadid=14894

Fuel gauge: I suggest correcting the above and looking hard at other solder joints, breaks in flex, so forth. If that does not help, then locate the yellow/white wire in a connector under the master cylinder. This is the lead from the fuel sender. Open the connection. One side goes in the firewall, the other goes underneath. Measure the yellow/white wire resistance to ground. It should be roughly 20 - 200 ohms. Next, estimate how full the tank is, and post it here with the resistance reading.

Temp gauge: There is a one lead sensor, I think around the thermostat. It should be varying resistance with engine temp. If not, the sender is dead. 74 ohms is cold, 9.7 ohms is hot.

Did you change the entire cluster as a unit (all gauges, flex circuit, etc...)? Also, did these symptoms change AT ALL when you swapped the cluster?

I guess what I am trying to say is that it is just odd that all the gauges are screwed up at the same time, yet swapping the cluster didn't do anything to fix it. You have power to the gauges because they do deflect to some degree. You may just have a coincidental case of sender/wiring failures.

The information and color codes are from a '94 book. They should be the same, it's the best I can do for you.

 

[Everdream]

I pulled the whole cluster piece by piece to make it easy..
Popped the small screws around the clear plastic,pulled it nd pulled the black liner.

I Pulled all of those gauges out, alot of them had the "cans" on the back a burned color.

I popped the clips by pushing the tabs that show through the dash once the gauges are pulled out, than unscrewed the PRNDL selector, pulled the speedo forward and pushed the white part backwards and popped the speedo cable.

I replaced all this stuff In reverse order with a known working cluster (also disassembled it same way and snapped it in, all piece by piece.) the one difference is that my fuel gauge with the truck OFF moves up a little (its not always "bottomed out".

I will look at the rest of that stuff, somethings gotta give. this new cluster does the EXACT same thing the old one did, gotta be some sorta wiring issue.

 

[Everdream]

I should add, I replaced it all, the white/blue circuit board included, I just disassembled it piece by piece to make it easy. New board looked perfect, no black marks or burns or other anomalies.

 

[Roadrunner777]

Did you get the truck like this or did they fail on you one by one, or all at the same time?

So, you never had the entire cluster unit out... just the modules? Because, there are connectors going to the back of the cluster, and they are tough to connect. Someone may have missed latching one and now you are seeing this mass gauge failure.

 

[Everdream]

Purchased it this way, but no fuel gauge is kinda pissing me off, so I decided to try and tackle it. do you have a picture of the connector im looking for under the hood with the wht/ylw wire? mine are a little moved around, I have the one going into the firewall (large circle, about 54535 wires) a two grey plugs w/ 4 wires each, one 8 plug wire next to that, some light sockets? or something that go to junk I don't have... thanks for making me realize i need degreaser

 

[Roadrunner777]

It has about 8 wires in it... I have a '94 and this is the kind of junk they change. My connectors are blue, white and grey. I think it's the grey one, but I am covering some phones right now so I can't really go out and break it down.

 

[Everdream]

Well, I found that wire you're talking about I think, I unplugged a connector with 8 wires going into it, facing front to back near my brake cylinder like you said. I than found under a black wire a yellow and white one, and after putting my ohm meter to "200" in the "OHM" setting, I probed it, the resistance was about 14.4OHMS (there is gas in the truck, more than 25 bucks worth), I than went and looked in the truck, and turned on the key, and the gauge while unplugged went to full. This leads me to believe than, that based on what I've read, the problem lies between the sending unit and the end of that plug (likely the float ball or sending unit?)
What do you think?

Thanks man

 

[Roadrunner777]

You have it under control and understood. It it's 14 ohms rock solid, you can retest nearer to the tank, but it's looking like the sender to me. Sorry, I think you are going to have to go back in to fix this. Spec is 22 ohms on the E of empty. Your float must be sitting on the bottom of the tank.

 

[Allen35540]

Having the following problem with my instrument cluster:

Tachometer Stuck at 3200RPM(ish) while running) moves up but not down.
Fuel gauge not working.
Low Oil pressure all the time (about half way up, never moves, even after a oil change)
Engine always says its about a 1/4 over in the cold zone.
these all "return" to their correct zones when the truck is off (the fuel gauge moves up to about 1/4 with the truck off)

Where does this tach get all its information from? Replaced with new gauge cluster, same symptoms. speedo works fine.

I don't know where to go with this problem, Id like my fuel gauge to work, and I'm hoping its not the sending unit in the tank, im leaning towards the wiring to the gauge itself because of all the other gauge problems.

thx guys

1992 Ford Explorer XLT 4.0L Automatic 4x4.

I've heard of this happening before. It may be the Instrument Voltage Regulator. These gauges need a steady voltage to read correctly and if this item is not working correctly you might get this and it appears to be affecting all of your gauges which would make me suspect that regulator.

 

[Everdream]

Do you know anything else about this, and would it be part of the cluster I replaced at all? This sounds like a viable response, considering the temp gauge is always near cold, and the tach sits at 3200 while the trucks running. I really just want the fuel gauge to work, and Id like to not have to pay 60-100 bucks for a sending unit and than have to mess with pulling the gas tank out and such. I dont have to tools or space for that type of job (and I'm not paying a shop)

 

[Roadrunner777]

You could take out the full cluster (4 screws in the corners, 2 connectors and speedo cable) and look at the flex circuit in the back... may see something there relating to the other issues. While you are there, replace your instrument backlights... there is no better time.

If your measurements were correct on the gas tank, your problem is in the tank though...

 

[Allen35540]

Everdream: I think it would be part of the circuit board that is on the back of that cluster. More than likely it will be a 5-volt or an 8-volt regulator and it is in a TO-220 type case arrangement. Your best bet would be to replace that circuit board. The reason I think it's a regulator is that when you measured the voltage on the tank, it was low and that's how regulators generally start to fail. If you bought a new cluster, than maybe there's a problem with it and you can get another one on warranty. I have found that when there is a problem with voltage regulation, things like this can happen. You should also be aware of another module standard to all Fords, the CCRM, (Constant Control Relay Module). Frequently this one not only holds the main relays but applies regulated voltage to a lot of circuits. Problems with this can affect systems throughout the car in a major way, almost everything is tied into it. If there is no regulator in the cluster, then it's getting it's regulated voltage from that module. In that case it could be a bad wire or contact from the CCRM that is causing that to happen. You can determine if your float has a problem by measuring resistance to ground from the sensor output terminal, then drive the car for awhile and measure it again. If the float is bottomed, there will be no change. If it is not, there will be a change and that would indicate a reference voltage problem. Also double check the instrument panel grounding. It could be as simple as a bad ground to the circuit board on the back of the cluster. Measure from board source to the chassis. If you don't get continuity, this is your problem. I run another wire to the chassis from that point when this happens as it indicates an internal break in the wire and is difficult to find and fix. Good luck on this!

 

[Keno Biebrich]

Wow

Everdream: I think it would be part of the circuit board that is on the back of that cluster. More than likely it will be a 5-volt or an 8-volt regulator and it is in a TO-220 type case arrangement. Your best bet would be to replace that circuit board. The reason I think it's a regulator is that when you measured the voltage on the tank, it was low and that's how regulators generally start to fail. If you bought a new cluster, than maybe there's a problem with it and you can get another one on warranty. I have found that when there is a problem with voltage regulation, things like this can happen. You should also be aware of another module standard to all Fords, the CCRM, (Constant Control Relay Module). Frequently this one not only holds the main relays but applies regulated voltage to a lot of circuits. Problems with this can affect systems throughout the car in a major way, almost everything is tied into it. If there is no regulator in the cluster, then it's getting it's regulated voltage from that module. In that case it could be a bad wire or contact from the CCRM that is causing that to happen. You can determine if your float has a problem by measuring resistance to ground from the sensor output terminal, then drive the car for awhile and measure it again. If the float is bottomed, there will be no change. If it is not, there will be a change and that would indicate a reference voltage problem. Also double check the instrument panel grounding. It could be as simple as a bad ground to the circuit board on the back of the cluster. Measure from board source to the chassis. If you don't get continuity, this is your problem. I run another wire to the chassis from that point when this happens as it indicates an internal break in the wire and is difficult to find and fix. Good luck on this!

 

[Keno Biebrich]

05 explorer flex fuel gauge gas full tank, mark half

had this problem, full tank and mark the gauge gas half tank, change the pump fuel and the problem no resuelt, any help

 

[larrydd999]

There is a well-known issue with the Gen1 Explorers regarding the fuel tank sender. Eventually the float develops a hole, fills with fuel, and drops to the bottom of the tank. I've seen it here numerous times and had it happen to our '92. We lived with it for some time, using the trip meter to keep track, but eventually I had a shop change the sender and the entire in-tank assembly including the pump. With over 200k miles and it being my wife's DD I didn't want to take chances.