Chrysler Repair: TC Instrument cluster flashing, car repair manual, hazard flashers

Question
Hello, I have a 2005 Town and Country and as I am driving the instrument cluster will momentarily go black and then light back up again. Usually this happens within one second. Just before the cluster goes black the dials for the speedometer and rpm move erratically. At the same time I usually hear a single 'ding' coming from somewhere in the car.    I have a new month old battery. the terminal on the battery are tight. I have bought the chilton car repair manual and have tested the battery,evr, and alternator for the correct voltage, and they do produce the correct voltage. I have started the car, with me wiggling all the wires that can be seen under the hood, while my wife views the instrument cluster for signs of failure but it does not happen. It appears to happen when it is very hot outside and I am running my air, and the car has been running for at least 15 minutes, but it is very random. Only once has the car stalled, after attempting to leave a bank ATM machine. This is driving me crazy and my wife is afraid to drive the car. Please help.

Answer
Hi Gene,
In some respects this is simpler than might be imagined and in some respects not. The cluster has only one power supply wire and that one comes from fuse #24 in the intergrated power box under the hood on the left inner fender which has all the fuses and relays inside. That fuse is probably ok (but check that it is in the socket and cleanly connected to the pins of the socket, but beware because one side of the socket is 'hot' at all times), but there is associated with it a small component called a diode which is attached to the downsteam side and which smoothes out the voltage source to block electronic switching noises coming from elsewhere in the wiring. That diode might be breaking down and then recovering is one posibility. The other system that is fed by that fuse is the hazard flashers and so if you found that it too was doing the intermittent cut-out then that would pretty much prove that power supply diode was the cause of the problem. It could be replaced by soldering in a replacement, but I can't give you the exact specifics without having a box to inspect, It does pivot 90 degrees so you can inspect both the top and the bottom side and maybe see the diode attached to the fuse socket. As that socket is supplied directly from the battery you would want to remove the fuse and only work on the side which is 'cold' (has no +12 on it, which is the side to which the diode is attached).
The other possibility is that the power carried by a wire from the fuse socket (brown/red in color) is ok, but the socket where it connects to the cluster (pin 6) has a flakey connection between the pin of the socket and the circuit board of the cluster. That too can be remedied with a soldering pencil by simply re-heating the joint. If that were the case, you often can shake it up by tapping on the top of the cluster when it is acting up (another diagnositic approach). But if this is momentary it would be hard to use that 'test'. If that were the issue you would need to remove the cluster which I can tell you how to do, based on the '02 manual.
So that would be my suggestion. I doubt that the car stalling is related in any way to the cluster issue.

Roland