Question: 2005 GMC Sierra. So i have a couple dash lights out and one came back on when i hit the dash but is now off again...also my prnd123 indicator light is usually not fully illuminated but once and a while will be when i start my truck. Any ideas as to what the problem is? Thanks!
Answer: For the few lights that only come on when you hit the dash cluster, that means the cluster has an internal problem and needs to be removed, sent for repairs, or have a rebuilt unit installed. After either repair, the dash will need to be programmed to your truck VIN # or it will not work properly. The gauges will not work and the odometer will show ERROR and not function.
For the PRNDL shift indicator, that could also be because of the cluster being bad, but can also be a bad gear indicator switch on the side of the transmission. This is pretty common. The switch and connector tend to melt together and cause this problem. But, with the dash acting this way, it would need further diagnosis to confirm that. A scanner with transmission range switch data, a schematic, test light and multimeter would be needed to test the switch.
Another possibility is a bad ignition switch for the shifter lights. That switch feeds power to the cluster and many other things. If it is putting out low voltage, it can cause this problem too. A tap on the head of the key and watching it will show if that is the problem.
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