dash gauges pegged full

[Brian Chavet]

I have two dash gauges in my 2000 Beaver Marquis that are pegged to the full clockwise position. They are the voltage gauge and the transmission temp gauge. On very rare occasions they will go to what I would consider their normal readout and within minutes or seconds they peg again. Any ideas on how to troubleshoot a possible grounding issue? Is this common and if so any ideas on the fix/replacement options? Thank you!

[Steve Huber Co-Admin]

Bryan,
Check the connections at the 2 gauges. I can't be sure but if the 00 Marquis is similar to the 01 Contessa, the nuts holding the connections to the gauge can come loose.
Steve

[Brian Chavet]

Hello Steve, thanks for the reply. I've checked the connections as best I can and all seems to be tight and in place. The wiring, however, is very difficult to trace. Also, I don't have anything even resembling a wiring diagram. I'm new to the forum, any ideas?

[Steve Huber Co-Admin]

Brian,
Go to the Private Members  Only board. Select the Coach Assist post and click on the hyperlink.  That will take you to the technical library. We don't have the 2000 Marquis but the 2002-2003 wiring diagrams should be very close. The dash gauge wiring is in part 4. (It is a zipped file and may take a bit of timer to download depending on your web connection).
Steve

[Eric Maclean]

Brian
Your volt meter should have an ignition source 12volts connected to the I terminal and a ground connected to the retaining bracket nut on the gauge with out either one of the two the gauge will read zero volts if the gauge is pegged it stays at full high voltage there is either too high a voltage at the gauge or the gauge is defective ( try tapping the gauge).
Take a multi meter and read the voltage between the I terminal and the ground terminal of the gauge to verify the voltage it should be reading .
The trans temp gauge should have 12 volts at the I terminal ( ignition on) and a ground at the retaining bracket but ( there will likely be several wires connected to the ground connection as they are all Daisy chained to one ground source ( the main harness)
The final connection is the S terminal this is the signal wire coming from the temp sensor at the trans if you disconnect this wire the gauge should drop to zero if it does then check the sender at the trans for resistance to ground .
With the S terminal back on the gauge disconnect the sensor at the trans again if the gauge drops to zero replace the sensor
If the gauge stays pegged check for a short to ground in the wire from the dash to the sensor.
Hope this helps
Eric