Oil Pressure Gauge

[kik]

Well after figuring out I probably have a bad channel on my amplifier. I buttoned the fairing back up and rode the bike to work this morning. I noticed on the way home that the pressure gauge was sitting below zero while going about 50mph. I pulled over and checked the oil and the level is fine. No oil lights are coming on and the bike runs well. How do I figure out if it's a bad gauge or oil sending unit? Does the gauge have a fuse? I looked in the service manual and it does reference the oil gauge but it describes how to test the fuel gauge. I checked the wires in the fairing none are broken or off. It's a 2000 FLHTC.
TIA

[kik]

OK I tested the wires at the gauge and I have 12v  So with ign.on I tested the wires at the sending unit. I tested across the leads and I have 3.86v. Does this sound right?

[Coyote]

1. Locate the oil pressure sending unit on the front right side of the crankcase.2. Verify that the electrical connector is properly connected to the sending unit.
3. If the oil pressure gauge indicates pressure but the low oil pressure light remainson, proceed as follows:
a. Remove electrical connector from oil pressure sending unit. Place one
ohmmeter probe on indicator lamp terminal (closest to latch), place the other
probe on the crankcase. Meter must read zero ohms.
b. Start the engine and run at a fast idle. The ohmmeter must read infinity.
c. Replace the sending unit if the above meter readings are
not
obtained.
4. If the low oil pressure light functions correctly, but the pressure gauge does not,then proceed as follows:
a. Remove electrical connector from oil pressure sending unit. Turn the Ignition/
Light Key Switch to IGNITION. The gauge must read zero.
b. Ground BN/GN wire terminal to crankcase. The gauge must read full scale 70
PSI.
c. Replace the sending unit if the above gauge readings are obtained. If the
gauge readings are
not
obtained, then replace the pressure gauge.

[kik]

OK, I disconnected the sending unit. With ign on I got zero with running fast idle I got 1.  Shut bike down Ign on ground wire from br/gn terminal to crank case gauge didn't move at all. Just a side note the needle is sitting below the 0 psi. So I guess this means the Gauge took a dump??

[Coyote]

Or the wire is bad from the sending to the gauge. Did you do a continuity test on both sending unit wires back up?

[rbabos]

OK, I disconnected the sending unit. With ign on I got zero with running fast idle I got 1.  Shut bike down Ign on ground wire from br/gn terminal to crank case gauge didn't move at all. Just a side note the needle is sitting below the 0 psi. So I guess this means the Gauge took a dump??

Either that or the engines pulling vacume.
Ron

[kik]

Yes I did do a continuity on both wires, they are good. So is there a preferred gauge brand to buy or should I just stick with the one from HD?

[jack744]

I've almost always found that when I work on something and have another problem after it usually has something to do with what I was working on . check allyour wires for pinching or broken ends.

[marc]

Yes I did do a continuity on both wires, they are good. So is there a preferred gauge brand to buy or should I just stick with the one from HD?

Can't go wrong with Rodger McEwin...They don't fog up on you either...


http://www.phatperformanceparts.com/ProductDetails.asp?ProductCode=GK61537&CartID=

[kik]

Thanks Marc, I'll check into that. Headed off to work this morning and the gauge is working again. Holding steady at 5 psi idle and 32 psi at 50 mph. So I have a feeling the winding in the gauge is shorting or the wires are breaking between the gauge and sending unit but the gauge didn't test well last night. If it happens again I'll just change everything and be done with it. Thanks for the help everyone, I really appreciate it.