Hey all.. Bought a very gently used and well serviced Ram 1500 slt big horn with the 4.7l a few weeks ago. (I upgraded from a 2002 Nissan frontier) Anyways, My check gauges light comes on at random times. Most notably when I enter the highway. The gauges are all in the "normal" range and do not flutter or crash like I have read in other posts. All fluids are good, no engine noise, no electrical anomalies that I can tell. The truck has 112,220 miles and looks like it has 10,000. The light clears when I turn off the truck and then comes back on after a few miles. I checked the voltage on the battery and after 20 minutes or so I noticed that it fluctuates a bit between 12.45 and 12.79. Also, the truck is not throwing any codes. Sorry this was a bit winded. Thanks in advance for any suggestions.

 

Are you checking the voltage when truck is running? It should be closer to 14V when running.

It sounds like a voltage regulator issue. Unfortunately in our trucks it's not on the alternator but it's a circuit in the ECU. I had a similar issue and ended up getting a salvage yard computer for $100 and had the dealer flush it. There's a guy somewhere in Florida that works on those. Do a google search and you should find him pretty quickly. Hope it helps.