Takeuchi TL140 Line Filter Warning Light Flashing

[lktowntn]

The line filter light is indicating that the line filter is plugged. Changed the line filter. The old filter appered OK but changed it anyway. Started it no change still flashing. Machine operates normally. The pressure switch on the end of the filter housing is showing open per meter when shut down and still open when running. The switch was remove and metered. It shorts when activated externally when press in and opens when released. The switch looks to be a differental pressure device.The wire to the pressure switch has 6.6 volts dc when the machine is running. According to the electrical diagram the instrument cluster is looking for the pressure switch to apply ground to give an indication of the line filter being plugged or when cold the hydraulic oil needs to warm up. Rung the wire back to the instrument cluster and it is good. So, is my instrument cluster the problem or am I missing something?

 

[Txhayseed]

Have you checked for a short to ground from the sensor itself ? If it shows open but your light is still on and it requires a ground to go active i would suspect the sensor or ground wire is giving you a false ground somewhere in the circuit

 

[skata]

Light still on with connector unplugged? Follow the wire to see if short to ground.

 

[lktowntn]

The sensor is open to ground both running with pressure and stopped with out pressure and with the wire lifter the light should go out and it did not. I lifted the line filter pressure switch wire while trouble shooting the circuit and should have included some more information in the beginning thread...My mistake! With the wire lifted I read almost 8 meg ohms to ground. I think that much resistance to ground would not cause the line filter light to flash and as stated in the original thread I have 6.6 volts lifted. I think that I would measure 0 volts if grounded. I checked a few other monitor circuits and all had 6.6 volts and when lifted almost 8 meg ohms to ground and they are working OK when their wires are shorted to ground as they are also looking for a ground to annunciate. I used both high and low impedance settings on my meter thinking I might have an almost broken wire with just a few strands for continuity but both readings were 6.6 volts and then I thought "Well Stupid" if the wire was broken and not grounded the circuit would never work. Hope someone out there can think of something I have not thought of before I spend almost $700 for a new cluster gauge. I think my next step is to disconnect that din connector as it only has circuits lookiing for a ground. If the light goes out then I missed something and if stays on then bad board. What do you all think?

 

[heymccall]

Are you chasing correct warning light?

 

[lktowntn]

Yes, Red w/white stripe. I have the above diagram in the Workshop manual on my computer and it is the same as the schematic above. By you having the schematic, it seems as though you have had experience with the TL140. Can you think of anything I have missed?

 

[lktowntn]

Final words, decided to totally remove the cluster gauge from the machine which is very difficult, not much room. The harness drawing in the shop manual does not show the connectors. There are four (4) of them, two rectangular M & F and two (2) bullet connectors M & F, which must be disconnected. (By the way, the field wires on the cluster do not unplug they are soldered.) After removal, we released and pushed the power (Y+) and ground (B-) pins out of their electrical connector. (The large rectangular connector which also has the R/W Line Filter Light wire.) Applied 12 volts dc to the pins and the Line Filter light started to flash so it had to be in the cluster. Purchased a new cluster gauge and installed. Line filter light now works correctly. Thanks for everyone's help!

 

[Txhayseed]

Well glad you got it figured out. They are a pain in the butt to get in there to. I always dread having to get in there to change out key switches which we do a lot. Taks are very well designed and easy to work on as far as skids go.. But for some reason they just decided they needed to make your day hard trying to get the switch/ cluster out... No slack in the wires no room to fit your hand ... Its a real pain... Sucks you had to buy a new gauge cluster.. Save your old one and send it off maybe it can be repaired.

 

[lktowntn]

Thinking about sending it off. Got any ideas as to where to send it?