[flightlead404]

Originally Posted by GrangerFox

Sounds like you’ve already done a solid round of diagnostics. Based on what you described:
• Gauge stays pegged at 5 bar even with ignition on and engine cold
• Still pegged with wire removed at the sender
• Goes to zero when the sender wire is grounded
• Also goes to zero when the wire is pulled from the back of the gauge

That does point more toward a faulty gauge than a sender issue, especially since grounding the sender wire brings it to zero (as it should). The fact that the gauge is foggy also suggests moisture intrusion or internal corrosion, which could be affecting its function.

If it were the sender, you’d typically see erratic readings or pegging that changes with engine temp or vibration. But pegged output even with the sender disconnected leans hard toward a short or internal fault in the gauge itself.

You might try:
• Pulling the gauge and checking for any corrosion or moisture inside the housing
• Cleaning or reflowing solder joints if you’re comfortable opening it up
• Replacing with a known good unit or testing with a spare if you have one

Let us know what you find — you’re definitely on the right track.

AI Bot