Howdy Y'all, I'm new to the site. I got an 05 Ultra classic and the oil pressure gauge isn't working and if it does work it's very irratic sometime the slower I go it will hold at 32psi and when I accelerate it will drop down to zero. any advice would be appreciated.

 

Change the sending unit. Not too expensive & easy to change.

 

It is relatively simple to troubleshoot for this problem.

1.) Unplug the Oil Sender Connector. The sender is located on right front side of the crankcase, just behind the exhaust pipe.
2.) Examine the sender connector and the harness connector for corrosion
3.) There are 2 pins in the connector – pin A is the Low Oil Pressure Switch, the other pin “B” is the Oil Sender Input to the gauge. The circuits get ground through the case of the oil sender and chassis.
4.) Check the Sender first using an ohmmeter:
- Verify you have continuity between pin A and chassis (negative Battery) – should read less that 10 Ohm
- Verify resistance between pin “B” and chassis – should read more than 150 Ohm
- While still connected to pin “B” and chassis start the engine – the meter should read between 30 and 100 Ohm
If any of the above does not check out – replace the Oil Sender

5.) Check the wiring to the Oil Pressure gauge (work with the mating connector on the harness side):
a. Turn Ignition ON
b. Verify the back lighting of the gauge comes ON
c. Using a wire jumper short pin “A” to chassis – verify your Low Oil Pressure warning Light turns ON
d. Using a wire jumper short pin “B” to chassis – verify your Oil Pressure Gauge hand deflects all the way to full stop
If any of those steps don’t pan out then you have open connection to the gauge, or the gauge itself failed.

As Jinks suggested the most probable cause is the Oil sender; next one is open wire.

It would have been helpful if you could say how exactly the gauge was not working:
- Is the Low Oil Pressure light ON when you turn Ignition ON (should be ON)
- Is the Low Oil Pressure light ON when you start the engine (should be OFF)
- Is the back light of the gauge ON with Ignition ON
- What the gauge is showing with the engine running – zero PSI or more than 65 PSI?

 

Thanks guys I'll be getting after it first thing in the morning. I'll let ya know how I make out

 

I also installed the air temp and oil pressure gauge and new oil sending unit on my 03 FLHTI,running light comes on on the oil pressure gauge, but no reading, nothing. I wired everything according to direction. I know kinda hard to diagnose here but any ideas?

 

if you don't mind please read my previous post above, it describes in sufficient detail how to troubleshoot for this problem

 

I got my guage working, It was the connection down at the sending unit. I just cleaned up the posts and the female connector I am now getting 32psi now. I have found that this guage does not respond has fast as the one on my 07 streetglide Thanks for all the help!