The oil pressure indicator is showing no oil pressure in the lower of our LTM 1200/1, the oil filters are on top of the engine which we replaced with new filters and they are getting plenty of pressure to the filter, but the indicator remains the same. Any suggestions?
Find the pressure sender. Pull it out. Put in manual gauge. Crank engine and verify oil pressure. If it's a 3 wire sender, verify power and ground. If it's a 2 wire, verify power to sender. You should be able to jump the leads and test function of the gauge or light on the dash. If all that is good, you need a sender. If you don't have that, you need to look for broken wires or something else on the circuit pulling it down. An electrical diagram is almost essential.
If sending unit is good it may need the pan dropped and the pickup cleaned out as well as new o-rings in the pickup tube. I've seen quite a few Mercedes and Detroit engines with those issues.
All those sender's come straight from circuit boards don't jump the terminals
I guess this is a Liebherr engine. From what I can find, the sender is just a 2 wire switch. It's either normally open or normally closed. It's not going to hurt any circuit boards. I wonder if the upper motor has the same pressure switch. Might be able to swap them quickly and see if the problem remains.
We talking gauge or light when you say indicator. If it's normally open or normally closed its only running a dummy light. Gmks have all the gauges in your lower ecos screen. Jumping the terminals would only cause an error code. Ltm1200/1 would be a little older so it may have a simple 2 wire sender. Until you get your hands on schematics it's gonna be hard to tell. If it's getting oil pressure to the filter you know the problem is in the gauge/light circuit.
Well, if it's an actual pressure gauge, the sender would be a variable resistor. You'd need to figure out the base resistance to test the instrument panel with a known good resistor. Without a schematic and some info on the sender it would be hard to know. Most automotive stuff is in the 100 ohm range. Surely Liebherr would not design their own custom pressure sender. But then again, it is German...
The Germans are more logical than the Italians that build our drilling rigs. Well that or the 25% German in me helps in the understanding Dept! Lol. They all do some funky stuff.