Temperature Gauges reading off, Where to start

[RJM]

On a recent shakedown run, I discovered one temp gauge is frozen and the other reading hot. One of them set off the temperature alarm. We checked the running engines with an infrared thermometer gun and both were in the 170-175 range and remained there. I need to diagnose this first, but If I have to replace anything which I suspect I will, I want to upgrade to get NEMA 2000 signals and am looking for input. Thoughts on diagnosing, etc.?

[rustybucket]

I second this question. I have a digital system in place but I love my dash gauges and one of my temp gauges went wonky last trip. It appears to work until you throttle up at which point it pegs, while the actual engine is running 185, where it always runs, verified by digital temp sensor and also IR gun on engine.

I guess the 3 possible suspects I come up with are sender unit, gauge or wiring/connections. Not really sure how to trouble shoot it though.... There is not much room to work with up in there.

[doc g]

1). try switching the wires stb side to port side and see if the problem follows
2) . Try having someone ground out the sender wire and see if it pegs the gauge, most gauges will go to full when grounded.
3). Disconnect the wires at the sender and gauge then see if you have continuity to ground with the wire d/c'd.
4). Try switching senders p to stb which is the same as switching the wiring.
Hope this helps. I have found that sometimes when a sender gets warm it will short and peg the gauge and set off alarms.Make sure with IR gun that you are not overheating first. ....Pat

[SEVEN]

If you repair or replace the gauges please let us k ow who you went with. Mine run at 175 to 180 at WOT. However I have one transmission gauge that is off and I’d like to have it repaired. I installed a permanent remote gauge gauge to verify the correct reading.

[racclarkson@gmail.com]

I’m curious about that alarm.