QuestionQUESTION: Started truck yesterday my headlights/tail lights went on by themselves. no dash lights,odmeter,techodmeter,speedodmeter, wipers,no flashers and no signal lights and next to the temp gadge is a little sold red light that is on. and the automatic door locks don't work, Other then that the truck ran fine. I check the battery, disconnected the battery, hoping it may reset the problem.... checked the fuses.. I also had the battery and alternator tested and are both fine.. At a loss what this could be
ANSWER: Hi Ryan,
That behavior you describe is symptomatic of an issue that involves a short or open circuit between the headlamp switch and the instrument cluster. That cluster is a rather significant module in the electronics of the vehicle. Before opening the dash to remove the cluster/check the wire connections, you might want to try a fault code readout using the self-diagnostic capability;
Press the odometer/trip odometer and hold it, turn the ignition switch to the "on" position, then release the button. The cluster will go through a number of tests of all the gauges, etc and then it will display some coded fault information in the odometer window in place of the mileage reading. Write down each such displays and let me know what they are. When "00 00" is displayed the readout is over. Tell me what coded info appeared in the odometer window.
Please read the PS (below) and respond to it.
Roland
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QUESTION: Hi Ronald
I did what you suggested, however the whole dash is black... no odometer reading at all, no codes... nothing moves, no gauges movement
ANSWER: Hi Ryan,
Then check fuse 18,22,41 to see if any of those is blown. There is also different sort of fuse like device called a positive temperature coefficient circuit breaker and there is a location in the same box for 5 of these but only 1,2,and 5 slots are filled. Check the PTC #2 (4.5 amp) to be sure that it is showing 12v on both ends of it. Those are the fuses/PTC listed for the instrument cluster in my '04 manual which I believe applies to your '02. One of those 4 devices must be blown.
If you would do a rating and nomination of me that would be most appreciated.
Roland
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QUESTION: Hello Again
Checked fuses 18,22 & 21 all ok.... Not sure what you mean by different fuses for slots 1,2 & 5 ( a different color maybe) but checked the fuses in those slots and appear to be ok... for the lack of sounding stupid what is the PTC #2 and am I checking this is the same place as the other fuses under the hood?
AnswerHi Ryan,
ALSO Check fuse 51 (20 amp) as it also powers the instrument cluster.
The PTC's are similar in size and shape to fuses but have a white body rather than glass body. There should be three of them in the same box together, in a holder which has spaces for 5 of them. My drawing doesn't show exactly where they are unfortunately. The output of that PTC comes out of the box on the gray color plug on the back side which has 26 pins and specifically it is a pink/yellow wire on pin #3 of that plug. It should show 12v with the key in the run position if the PTC is good. Also check that both sides of fuses 18, 22, and 41 all show 12v with the key in the run position to prove that the fuses are patent.
For the cluster to be dead I would believe that one of these 4 fuses is bad.
The other possibility is that one of the ground wires of the cluster itself is bad which are on pins 13 and 14 of the white plug at the cluster and pin 13 of the gray plug at the cluster, and pin 4 of the headlamp switch. You could check for continuity (0 ohms resistance) to the chassis of those 4 pins. Those wires go to a ground point on the fire wall under the dash just to the right of where the power outlet is located so if those wires don't show continuity to ground then you would go under the dash to find a screw that receives a lot of black wires that attaches them to the body at that point.
I hope one of these tests will reveal the cause of your problem. Otherwise the cluster itself may have gone bad.
Please, may I request that you rate/nominate me for each of my three answers to you?
Thanks,
Roland
