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ricky881 02-11-2012 07:28 AM

Dash lights stay on no gauges wj 4.7
Hi the dash lights are staying on after starting my jeep and the gauges wont work. it drives ok but is very annoying as I have no idea how fast and how much gas I have as well as what if anything is going on with the engine management and other systems. Has anyone experianced this fault? thanks ricky

Frango100 02-11-2012 01:34 PM

Re: Dash lights stay on no gauges wj 4.7
Check first fuse 17 and 22 on the junction block under the steering wheel.
If ok, do a test of the instrument cluster. To do this, with the ignition switch in OFF, press the odometer button and while pressing it, switch the ignition in run. Now release the odometer button and the instrument cluster starts the self test, all indicators go full scale and return, all lights will be on and the odometer will count 1111111, 22222 etc. If this all is ok, at least the instrument cluster is ok. There could be a problem with a loose PCI data bus wire at the back of the cluster.

ymaqousi24 12-18-2014 01:20 PM

Re: Dash lights stay on no gauges wj 4.7
Did you ever find out what it was causing your gauges to go out? Because my 2000 4.7 GCL is doing the same thing. I've checked the battery terminals and found 3 inches of corrosion on the positive battery cables. I cleared it up and the gauges returned to normal for a little while then one by one died. Weird thing is i get like glimpses from my gauges every now and again.

Frango100 12-18-2014 04:59 PM

Re: Dash lights stay on no gauges wj 4.7
Did you try the instrument test, to see if the panel works ok?
Does the engine start normally and are power windows and power locks working?

ymaqousi24 12-18-2014 06:02 PM

I did the test and it works. Car starts and runs great! The gauges work when the cars engines not running but once It starts they die one by one. But if I disconnect the battery for ten minutes and reconnect they'll work for about an hour but only to die later on.

ymaqousi24 12-18-2014 06:05 PM

I've gotten several codes but don't think there right. P1698, P1686, and P1685.

ymaqousi24 12-18-2014 06:06 PM

I'm thinking a short in the wiring somewhere but don't know where to start.

Frango100 12-18-2014 09:22 PM

Re: Dash lights stay on no gauges wj 4.7
The instrument cluster receives its information from the PCM via the PCI data bus. If no information is received, then it will put the instruments on zero and light up the indication lights. That it happens one by one, means that the bus itself is not shorted. You could measure the PCI data bus voltage at the moment the problem is there, maybe that can tell something. A healthy bus shows 2-2.5 V. When it shows 0 V, then the bus is shorted somewhere. If is shows 7 V, then a component on the bus is faulty and pulling the bus power up. You can measure the bus on the diagnostic plug under the instrument panel at pin 2.
For now i would expect the PCM, but it still can be something else.
I would check the PCM connectors for moisture/dirt/corrosion on the pins and clean them with contact cleaner.

ymaqousi24 12-18-2014 09:49 PM

I just replaced the pcm with a "completely remanufactured" PCM so it's possible but I hope not. But my gauges worked fine before I put the new one and immediately after I put it in I started getting check gauges warnings and my oil pressure gauge was acting funny . Now none of my gauges work. I'm going to try the contact cleaner in the morning and hope that's it.

Frango100 12-20-2014 06:12 AM

Re: Dash lights stay on no gauges wj 4.7
I would check the PCM connectors for tight fit and check if no connector pins are pushed back or bend. If that is ok, then most probably the problem is with the PCM. You donīt have warranty on it?

ymaqousi24 12-20-2014 11:32 AM

Re: Dash lights stay on no gauges wj 4.7
I do have a lifetime warranty. I cleaned all the connections with contact cleaner and plugged everything back up and got the same results. Gauges stayed on for the entire drive to work but the Sentry light was on? But on my way home when I started the jeep the gauges died and lit up like a Christmas tree.

Frango100 12-20-2014 01:38 PM

Re: Dash lights stay on no gauges wj 4.7
To me this looks as a problem with the PCM.

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